Xichang Qionghai Hotel
We are pleased to announce that the XIX International Conference on Topics in Astroparticle and Underground Physics (TAUP2025) will be held at the picturesque Qionghai Hotel, situated along the beautiful lakeshore in Xichang, Sichuan Province, China, from 25 to 29 August 2025. TAUP2025 is designed to convene theorists and experimentalists in the field of astroparticle physics to assess and deliberate on the current state and future directions of our discipline's thematic areas, including cosmology and particle physics, dark matter and its detection, neutrino physics and astrophysics, gravitational waves, high-energy astrophysics, and cosmic rays. Xichang serves as the support city for the China Jinping Underground Laboratory (CJPL), and we are delighted to offer guided visits to the CJPL for our registered participants on August 24 and August 30, 2025.
Conference location: Xichang Qionghai Hotel（西昌邛海宾馆）
Address: 115 Haibin Middle Rd, Xichang, Liang Shan Yi Zu Autonomous, Sichuan Province, China, 615099.
The recommended accommodation can be found in Venue and Accommodation.
No travel agency is involved in this meeting, please ignore any request from them.
Conference Fee：
Student/Postdoc: CNY 2300.
Faculty/Staff, etc.: CNY 4600 (Regular Registration from 1 July 2025 to 1 August 2025) or CNY 4000 (Early bird before 1 July, 2025)
The conference fee includes registration, conference material, coffee breaks, reception, and Banquet. It also covers the cost of the visit to CJPL.
Accompanying person Fee: CNY 2300 (Regular Registration from 1 July 2025 to 1 August 2025) or CNY 2000 (Early bird before 1 July, 2025)
The Accompanying person fee includes registration, coffee breaks, reception, and Banquet. It also covers the cost of the visit to CJPL.
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Visit CJPL CJPL
CJPL
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On-site registration (start at Saturday 23/08) International Conference Center
International Conference Center
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On-site registration (start at Saturday 23/08) International Conference Center
International Conference Center
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On-site registration (start at Saturday 23/08) International Conference Center
International Conference Center
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Welcome session Lufeng Hall
Lufeng Hall
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Plenary session Lufeng Hall
Lufeng Hall
Convener: Zhi Zeng (Tsinghua University)-
1
Neutrino theory (neutrino masses, mixing, and interactions)
This talk presents selected aspects of neutrino theory and phenomenology. We take a low-energy perspective, considering neutrino mass as an EFT extension of the Standard Model, stressing the unique oportunity of neutrinoless double-beta decay to test this hypothesis. We give a brief overview of the present status of the three-flavour paradigm, high-lighting its success, as well as pointing out possible hints for deviations from it. We argue that current data does not suggest that sterile neutrinos participate in oscillations. We discuss the emerging tension between results from cosmology and terrestrial experiments regarding the neutrino mass, offering exiting prospect in the near future.
Speaker: Thomas Schwetz -
2
Neutrino oscillation experiments (Reactor, atmosphere, long baseline)
I will review the current status of reactor, atmospheric, and long-baseline accelerator neutrino oscillation experiments, with a focus on the parameter constraints within the three-flavor oscillation framework. Thanks to a wide range of experiments, we now have increasingly precise neutrino oscillation measurements across a broad spectrum of energies and baselines. This is significant for two reasons. First, the consistency of results across experiments — despite differences in detector technologies, neutrino sources, and interaction channels — demonstrates successful control over systematic uncertainties at current statistics. Second, while individual experiments only probe specific projections of the oscillation parameter space, leading to various degeneracies in parameter inference, the combination of results from multiple experiments helps to both lift some of these degeneracies and test the validity of the three-flavor oscillation framework. Future prospects and remaining challenges will also be discussed.
Speaker: Lukas Berns (Tohoku University) -
3
Single and double beta decay: Probing neutrino mass and nature in the laboratory
The absolute mass and fundamental nature of the neutrino are still undetermined. Beta decays are unique tools to probe them in the laboratory. While the kinematics of single beta decay enable model-independent measurements of the neutrino mass, the observation of neutrinoless double beta decay would identify neutrinos as Majorana particles. In this talk, I will present the current status, latest results, and future prospects of direct neutrino mass and double beta decay experiments.
Speaker: Christoph Wiesinger
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1
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Group Photo, Coffee break International Conference Center
International Conference Center
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Plenary session Lufeng Hall
Lufeng Hall
Convener: Art McDonald-
4
High energy astrophysical neutrinos
This lecture will cover the status and perspectives of neutrino astronomy that opened a new unique observational window on the high energy Universe where the most violent phenomena take place. Neutrino astronomy was born in 2013 with the observation of a cosmic neutrino flux made by IceCube at South Pole. The realization of deep underwater/ice Cherenkov neutrino telescopes is a very challenging enterprise where new technologies were developed and validated leading also to the construction of telescope prototypes (AMANDA, ANTARES, BAIKAL) paving the way the construction of km3-scale detectors. The full coverage of the neutrino sky requires telescopes located in different regions, at least one in the Southern hemisphere and one in the Northern hemisphere.
Several observations provided hints on high energy neutrino sources. In particular, the observation of a very energetic neutrino from the blazar TX560+056 which inaugurated the era of multi-messenger neutrino astronomy and the evidence for neutrino emission from the active galaxy NGC1068 by IceCube were the first indications of high energy neutrino sources. More recently, KM3NeT, still under construction in the Mediterranean Sea, detected an ultra-high-energy neutrino of 220 PeV KM3-20230213, in a totally unexplored region of extreme interest for astroparticle physics. Several questions are however still open, in particular, classes of astrophysical sources that explain the data as a whole has not be identified so far.
In order to solve the open problems and increase its discovery potential, neutrino astronomy requires a strong synergy between running telescopes (IceCube, KM3NeT and GVD) and new projects (HUNT, TRIDENT, P-ONE…) and the strengthening of multi messenger astronomy.Speaker: Piera Sapienza -
5
Coherent neutrino scattering, searches for sterile states
The presentation will review coherent neutrino scattering and searches for sterile neutrinos. It will cover the status and recent developments of experiments in the field, new results and it will indicate perspectives for the future.
Speaker: Manfred Lindner (Max Planck Institute for Nuclear Physics) -
6
A theory overview of high-energy cosmic neutrinos
Please supplement the content of the abstract.High-energy cosmic neutrinos hold vast potential to propel particle physics and astrophysics forward. They have the highest detected neutrino energies---up to the PeV scale and beyond---and travel the longest distances---up to billions of light-years, the size of the observable Universe. These unique properties make them piercing probes of particle-physics properties, possibly tiny in size and emerging only at extreme energies, and of the most luminous, violent, and distant astrophysical phenomena of the Universe. Realizing this particle-physics potential is inextricably linked to understanding their astrophysical origins, and vice versa. I will discuss our current understanding of how and where these neutrinos are made, what we have learned over the past decade, and how we can extract robust constraints on neutrino properties in spite of astrophysical uncertainties. Finally, I will outline how the forthcoming generation of neutrino telescopes will dramatically sharpen these tests, simultaneously constraining fundamental theory and revealing the nature of the Universe's most powerful particle accelerators.
Speaker: Mauricio Bustamante (Niels Bohr Institute, University of Copenhagen)
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4
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Lunch Yu’ou Building
Yu’ou Building
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Cosmology and Particle Physics: parallel session 1 Conference Room F1-R3
Conference Room F1-R3
Convener: Huaike Guo (中国科学院大学（ICTP-AP）)-
7
Connecting inflation and the baryon asymmetry with neutrino reheating
Connecting inflation with neutrino physics through non-thermal leptogenesis via direct inflaton-right-handed neutrino (RHN) coupling naturally incorporates neutrino reheating, leaving no ambiguity regarding the early history of the Universe. We demonstrate that non-thermal leptogenesis from inflaton decay expands the viable parameter space compared to thermal leptogenesis and provides a natural link to inflation. By closely examining the dynamics of neutrino reheating, we establish a direct connection between baryon asymmetry and the spectral index for the first time. This approach places these two important observables on the same plane and yields specific predictions that help break the degeneracy among inflationary models. The well-motivated and economical framework offers a simple, natural, and testable description of the early Universe.
Speaker: Xinyi Zhang (Hebei University) -
8
Gravitational waves of GUT phase transition during inflation
Grand unified theory (GUT) phase transition is generally considered unobservable due to its ultrahigh energy scale, and the monopole problem associated with GUT phase transition is one motivation of inflation. We propose that if a first-order GUT phase transition happens during inflation, the induced gravitational waves (GWs) are redshifted and deformed, and might be observed today in GW observatories. We review the formalism of inflated GWs and derive the general deformation function between inflated and uninflated GW spectra in the instant-source or transitory-source application. It is valid for any e-folding number of instant or transitory source. Applying the formalism to GUT phase transition, we find that the e-folding number at 15 or 25 can shift the GWs to 10 Hz or mHz hands, respectively, which might be tested in the future ground-based or space-based interferometers. We further generalise the discussion to inflated GWs via phase transition below the GUT scale. It is worth mentioning that, due to the deformation of the spectrum, the peak of inflated GWs is not simply a redshift of the peak of uninflated GWs.
Speaker: Xi-He Hu (HIAS, UCAS) -
9
Reionization in the axiverse and the preference for low temperature reheating
Axions that couple to electromagnetism are produced in the early Universe by,among other channels, freeze-in of the Primakoff process. The same interaction causes theaxions to decay to two photons, which subsequently ionize the intergalactic medium. If this decay occurs in the range of redshifts 20 ≲ z ≲ 1100 then the contribution to the cosmic
microwave background optical depth τ can lead to a conflict with observations, and excludes models with sufficiently strongly coupled, heavy axions and high reheating temperatures, Treh. Using ensembles of explicit type IIB string theory models with 50, 100 and 491 axions
we compute the full reionization history caused by axion decay. We compare this to the posterior on the high-z component of τ derived from model-independent constraints on the high-z ionization state of the Universe in a full Planck analysis presented in a companion paper. We find that 50% of the models in the ensemble prefer Treh ≲ 10^11 (10^13) GeV at 68 (95)% C.L.. Our analysis opens the door for future large scale work studying the preference for low temperature reheating in models with multiple axions.Speaker: Ziwen Yin (Tsung-Dao Lee Institute & SJTU) -
10
Multi-Wavelength Probing of Primordial Black Holes as Dark Matter
Primordial black holes (PBHs) continue to be promising candidates for dark matter across several mass windows, providing opportunities for investigation through diverse electromagnetic observations. Spanning from radio to ultra-high gamma-ray frequencies, PBHs can generate detectable signals by integrating semiclassical phenomena—specifically, their Hawking evaporation and the their final bursts—with recently proposed quantum effects, such as “memory burden.”
The mass range of PBHs as potential dark matter candidates spans from $10^4$ grams to asteroid-scale masses. To constrain their properties, we employ data from the cosmic X-ray background (CXB), gamma-ray observations, and galactic source samples to delineate the parameter space. Moreover, our analysis uncovers previously neglected radiation processes across the pertinent energy spectrum, which could significantly tighten the constraints on PBHs. These processes encompass direct emissions from Hawking radiation, in-flight annihilation, the final state of radiation, and positronium annihilation.
We have established stringent constraints on PBHs within their plausible dark matter mass range and projected their detection limits through simulations of future experimental sensitivities.Speaker: Xiu-hui Tan (Institute of Theoretical Physics, Chinese Academy of Sciences) -
11
Can dark-matter Q-balls grow to the mass gap masses?
Within the framework of general relativity, it can be shown that gravitational waves are radiated with the merger of massive compact objects. Such gravitational wave signals are observed on Earth on various detectors, in particular, on Laser Interferometer Gravitational Wave Observatory (LIGO) and Virgo. During the operation of these detectors, many events have been detected. Those events are associated with the merger of massive compact objects; however, the nature of some merging objects has not yet been reliably established. This work considers nontopological solitons of dark matter—Q-balls, as candidates for the role of massive compact objects. In this work, one of the simplest models of Q-balls, the mechanism of their birth during a phase transition in the early Universe and the mechanism of their mass gaining during the evolution of the Universe, which is based on their mutual merger, are considered. As a result, it is analyzed whether Q-balls of dark matter can grow to the mass gap masses and be candidates for the role of massive compact objects.
Speaker: Alexander Libanov (INR RAS)
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Dark Matter and Its Detection: parallel session 1A Conference Room F2-R1
Conference Room F2-R1
Convener: Ning Zhou (Shanghai Jiao Tong University)-
12
WIMP results from XENONnT with 3.1 tonne × year of exposure
The XENONnT detector, operating with 5.9 tonnes of liquid xenon at LNGS, is designed for the direct detection of Weakly Interacting Massive Particles (WIMPs) in the Universe. Following the successful completion of its first science run in November 2021, the detector has now concluded a new science run in August 2023, leading to blinded analyses with an accumulated exposure of 3.1 tonne × year. In this talk, I will present updated results from XENONnT, covering both spin-dependent and spin-independent WIMP-nucleon interactions for WIMP masses above 10 GeV/c². I will also discuss signal & background modeling efforts undertaken to better understand the dominant sources of background, specifically accidental coincidences and double electron capture of Xe-124.
Speaker: Maxime Pierre (Nikhef) -
13
Results from and Status of the LUX-ZEPLIN Experiment
The LUX-ZEPLIN (LZ) experiment is a dark matter direct detection experiment operating almost a mile underground at the Sanford Underground Research Facility in Lead, South Dakota. LZ uses a 7 active-tonne dual-phase xenon time projection chamber primarily designed to detect weakly interacting massive particles (WIMPs), a well-motivated class of dark matter candidate. This talk will give the status of the LZ experiment, report on its latest world-leading dark matter results and discuss searches for other new physics phenomena.
Speaker: Amy Cottle (University College London) -
14
Search for light dark matter with PandaX-4T
PandaX-4T experiment has studied the ultra low energy data to enhance the sensitivity for light dark matter with sub-GeV mass. We combine ionization-only data and scintillation-ionization paired data to investigate five benchmark light dark matter interaction models, including spin-independent dark matter-nucleon interaction, spin-dependent dark matter-nucleon neutron-only and proton only interaction, and dark matter-electron interaction via heavy mediator and light mediator. Utilizing the commissioning run and the first scientific run, we set the most stringent limits in the mass range of approximately tens of MeV to several GeV. Especially for dark matter-electron interaction via light mediator, with the different treaments in signal model and reduced uncertainty in background model, the limit is greatly improved.
Speaker: minzhen zhang (SJTU) -
15
XLZD status
The XENON-LUX-ZEPLIN-DARWIN (XLZD) project represents the next step in the global effort to directly detect dark matter and explore neutrino physics using 60-80 tonnes liquid xenon time projection chamber. Building on the success of current-generation experiments such as XENONnT and LZ, the XLZD collaboration is designing a detector with unprecedented sensitivity to WIMP-nucleon interactions and neutrinoless double beta decay. In this talk, I will present the scientific goals, design concept of XLZD, and also discuss the current status of R&D efforts.
Speaker: Masaki Yamashita (Kavli IPMU, the University of Tokyo) -
16
Science prospects of the XLZD experiment
Liquid xenon time projection chambers have increased in size from kilogram to multi-tonne scale and provide the most stringent limit on WIMP dark matter-nucleon interactions for dark matter masses above $6~\textrm{GeV}/c^2$. These large detectors have simultaneously been able to reduce the background levels, due to radioactive impurities both in the detector structure and dissolved in the lXe by four orders of magnitude.
The XLZD collaboration is the next step in this evolution, where the XENON, LZ and Darwin collaborations have joined forces to design a single larger detector of 60 t or more of lXe for the next generation. This will allow probing the entire WIMP parameter space above where neutrinos become the dominant, indistinguishable background. I will present two primary science cases for XLZD— the search for WIMPs and neutrinoless double-beta decay searches.
Speaker: Knut Dundas Morå (Zürich University)
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12
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Dark Matter and Its Detection: parallel session 1B Conference Room F2-R2
Conference Room F2-R2
Convener: Tony Noble (Queen's University)-
17
Dark Photon Dark Matter Detection with Radio Telescopes
We propose utilizing radio telescopes to investigate the conversion of dark photons, a potential ultralight dark matter candidate, through two approaches: solar observations and direct telescope-based detection. In the first scenario, dark photon dark matter can efficiently convert into photons in the solar corona—the outermost region of the solar atmosphere—where the plasma mass of photons closely matches the dark photon rest mass. In the second scenario, the local absorption of dark photon dark matter can induce harmonic oscillations of electrons within the radio telescopes, producing a monochromatic radio signal detectable by the receivers. We analyze data from FAST, LOFAR, and the Parker Solar Probe to search for evidence of dark photon dark matter and to constrain its kinetic mixing coupling.
Speaker: Jia Liu (Peking University) -
18
Detecting Axion-like Particles: Long-Lived Particles and Dark Matter
Axion-like particles (ALPs) are hypothetical extensions of the Standard Model, with the potential to account for both dark matter and various astrophysical phenomena. This seminar will explore two distinct detection approaches for ALPs: one focusing on ALPs as long-lived particles and the other considering them as dark matter candidates. The first study (2410.16065) investigates the production of long-lived ALPs in stellar cores, particularly their decay into monochromatic X-rays detectable in nearby stellar systems. Using data from the Alpha Centauri binary system, we establish the most stringent limits on ALP interactions, improving constraints on the ALP-photon coupling by up to two orders of magnitude for masses between 0.25 keV and 5 keV. The second study (2507.07786) examines ALPs as dark matter candidates, exploring their conversion into photons via the Primakoff effect. By analyzing 16.5 years of Fermi-LAT data from the galaxy NGC 1275, we refine exclusion limits on the photon-ALP coupling for masses between 4e-10 eV and 5e-9 eV. We also highlight the potential of the upcoming Very Large Area Gamma-ray Space Telescope (VLAST) to surpass the sensitivity of future observatories like IAXO.
Speaker: Yue-Lin Sming Tsai (PMO) -
19
Dark photons and axion-like particles at the Electron-Ion Collider
The Electron-Ion Collider, a proposed high-luminosity facility with advanced charged particle and photon detection capabilities, provides unique opportunities to uncover new physics beyond the Standard Model.
We analyze its sensitivity to dark photons produced through electron bremsstrahlung in coherent scattering. Thanks to its beam energy settings, it has the potential to comprehensively probe the previously unexplored parameter space between the constraints from meson decays and beam dumps below $\mathcal{O}(1)$ GeV with displaced-vertex search.
Additionally, the EicC has the potential to probe axion-like particles (ALPs) in the mass range ( 0.1 \, \text{GeV} \lesssim m_a \lesssim 5 \, \text{GeV} ), with a coupling reach of ( \Lambda \lesssim 10^6 \, \text{GeV} ) , by combining the prompt-decay and displaced-vertex searches. The projected sensitivities to ALPs exceed the current bounds.Speaker: Teng Ma (ICTP-AP) -
20
Getting the most on SN axions
Core-collapse Supernovae (SNe) are considered among the most promising astrophysical laboratories to study the phenomenology of axion-like particles (ALPs). Because of the extreme condition of temperature and density reached in the core of the exploding star, ALPs can be copiously produced by means of their interactions with nuclear matter. In this talk, I will discuss how a large emission of ALPs during a SN event could induce observable signatures, as the shortening of the duration of the expected SN neutrino burst or the trigger of ALP-induced events in neutrino water Cherenkov detectors [1]. In this regard, I will argue that observations related to the SN 1987A neutrino burst can be employed to set stringent constraints on axion properties.
[1] A. Lella, G. Co', P. Carenza, G. Lucente, M. Giannotti, A. Mirizzi, T. Rauscher, ``Getting the most on supernova axions'', Phys.Rev.D 109 (2024) no.2, 023001 [arXiv:2306.01048 [hep-ph]].
Speaker: Alessandro Lella (Bari University, INFN Bari) -
21
Beyond the simplest strongly interacting dark matter
This talk focuses on the popular framework of strongly interacting massive particle (SIMP), where dark pion serves as the dark matter candidate. While it is well known that for SIMP the freeze-out process is typically 3DM ->2DM via DM self-interactions, I will show that the existence of other low-hanging composite states, such as sigma-like and rho-like dark mesons, can dramatically change the phenomenology and/or address other issues of the SIMP framework.
Speaker: xiaoyong chu (UCAS)
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17
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High-Energy Astrophysics and Cosmic Rays: parallel session 1 Conference Room F1-R2
Conference Room F1-R2
Convener: Piera Luisa Ghia (IJCLAB, IN2P3/CNRS, Orsay, France)-
22
Study of Muon Evolution in very High Energy Cosmic Ray Air Showers with LHAASO
The Large High Altitude Air Shower Observatory (LHAASO) has accomplished comprehensive and precise measurements of very-high-energy cosmic ray air showers. Leveraging data from the electromagnetic detector array and the muon detector within the KM2A array, accurate and composition-insensitive reconstruction of cosmic ray energies in the knee region has been achieved by measuring the numbers of secondary electromagnetic particles and muons produced in air showers. For the first time, the logarithmic shower muon number has been employed to derive the mean logarithmic mass ($\langle \ln A \rangle$) of cosmic rays, while fluctuations in the logarithmic shower muon number have been utilized to construct the variance of the logarithmic mass ($\sigma_{\ln A}^{2}$). The analysis provides a clear depiction of the cosmic ray mass composition evolution with energy and explicitly illustrates the energy-dependent trend of $\sigma_{\ln A}^{2}$. These results not only deepen the understanding of the cosmic ray source composition and acceleration mechanisms but also offer essential experimental constraints and robust validation for theoretical models regarding the mixed nature of cosmic ray compositions.
Speaker: Xiaoting Feng (Shandong University) -
23
Probing hadronic interactions at the 100 TeV scale with the Pierre Auger Observatory
Extensive air showers produced by the interaction of ultra-high-energy cosmic rays ($E > 10^{18}\,\mathrm{eV}$) in the Earth's atmosphere provide a challenging yet unique channel to probe hadronic interactions at the 100 TeV center-of-mass energy scale. Over more than 20 years of operation, the Pierre Auger Observatory has delivered invaluable insights into the modeling of hadronic interactions at energies beyond human-made particle accelerators. Notably, predictions from current models of hadronic interactions yield a muon deficit that becomes more pronounced with energy when compared to measurements. Presently, the interpretation of the nuclear mass composition estimated from the muon content is in tension with that from direct measurements of the depth of the maximum of electromagnetic profiles. Yet, the measured fluctuations of the muon content of air showers are in agreement with model predictions. These findings hint at small deviations in hadronic models that accumulate throughout the whole shower development rather than at large errors in the calculation of the first hadronic interactions. Also, in an independent data-driven analysis, we show that the muon deficit can be alleviated if we allow for a shift of the predicted depth of the maximum of air-shower profiles by 20 - 50 g cm$^{-2}$ towards a heavier mass composition. More recently, we have also provided an updated measurement of the proton-proton cross-section at center-of-mass energy 57 TeV and the first estimates of the neutron content of air showers by exploiting the late time signals at the surface scintillator detectors of AugerPrime, the present upgrade of the Observatory. With the advent of AugerPrime, we expect to deliver breakthrough results on the 100 TeV-scale hadronic interactions in the next decade.
Speaker: Eva dos Santos (FZU - Institute of Physics of the Czech Academy of Sciences) -
24
High-energy photonuclear reactions and muon content of extensive air showers
The observed excess of muons in extensive air showers (EAS) compared to Monte-Carlo (MC) simulation predictions emphasizes the need for a more detailed modeling of muon production processes in EAS. While numerous previous studies have primarily focused on the hadronic component of EAS, they have not yet provided a definitive solution to the muon excess.
In this work, we examine a subdominant source of muons in EASs: photonuclear reactions within the electromagnetic component of the showers. Using MC simulations, we have developed a semi-analytical model that, on the one hand, predicts muon yields over a wide range of experimentally allowed photonuclear cross-section models. On the other hand, our model directly constrains the high-energy photonuclear cross-section itself based on relevant EAS's observations.
We discuss the potential of our approach in explaining the muon excess.
Speaker: Nickolay Martynenko (Lomonosov MSU & INR RAS) -
25
Investigation of Muon Excess from Initial Hadronic Interactions in Cosmic Air Showers with a One-ton Scintillator Detector at CJPL
Over the past decade, ground-based array experiments have observed a notable muon deficit when simulating extensive air showers (EAS) induced by high-energy cosmic rays, compared to experimental measurements. This discrepancy is referred to as the muon puzzle. In this report, we present the first investigation on this topic at the China Jinping Underground Laboratory (CJPL), which, with its 2400-m vertical rock overburden, limits muons to energies above 3 TeV, with an average primary cosmic-ray energy of 0.4 PeV. This provides a clean window for studying the initial EAS processes. The data, collected over 1178 live days from the 1-ton prototype of the Jinping Neutrino Experiment, along with a GEANT4-based flux simulation framework, are used for comparison in this work. Our results show that the measured muon flux is approximately 30% higher than predicted, with a 2σ significance (3σ excluding model-related uncertainties), and no significant angular dependence is observed. These findings highlight the potential for future high-energy cosmic-ray research in deep underground environments.
Speaker: 昕舜 张 (清华大学) -
26
Seasonal Variation of Muon Flux in Daya Bay Using the Full Data Set
Primary cosmic rays interact with atmospheric molecules, initiating hadronic cascades in which mesons are produced. These mesons either undergo further interactions or decay into high-energy muons capable of penetrating rock and reaching deep underground detectors. Variations in atmospheric temperature influence the density of the atmosphere, thereby modulating the probability of secondary meson interactions. Specifically, an increase in temperature reduces atmospheric density, enhancing the likelihood of meson decays into muons. This results in observable seasonal variations in the muon flux detected in underground experiments. Numerous studies observed the correlation between the muon flux variations with temperature changes and extracted the corresponding correlation coefficients. Notably, the depth of overburden plays a critical role in these measurements, as it selectively shields low-energy muons whose parent mesons are less sensitive to temperature fluctuations due to their propensity to decay before interacting.
The Daya Bay Reactor Neutrino Experiment, with its three underground experimental halls at varying depths, offers an exceptional platform for investigating these effects. Leveraging a comprehensive dataset comprising over 14 billion muon events, the experiment enables precise determination of the temperature-muon flux correlation coefficients across different overburden conditions. This talk presents the current status of this analysis, utilizing the full dataset from the Daya Bay experiment to provide new insights into the relationship between atmospheric temperature, overburden, and seasonal variations in muon flux. The results contribute to a deeper understanding of cosmic ray interactions and their implications for underground particle detection.Speaker: Bangzheng Ma (Shandong University) -
27
MUTE: Calculations for Cosmic-Ray Muons in Deep Underground Laboratories
MUTE (MUon inTensity codE) is a Python program that performs calculations for cosmic-ray muons underground and underwater. It combines two state-of-the-art programs, DAEMONFLUX and PROPOSAL, to provide comprehensive calculations for muon intensities, total muon fluxes, energy and angular spectra, and mean muon energies at the surface, in deep underground laboratories — under both flat overburdens and mountains — and underwater. For precise modelling, the program takes into account rock densities and chemical compositions for various underground labs as well as topographic map profiles of mountainous overburdens. Our results show excellent agreement with available experimental data for most underground sites. Additionally, our model predicts the amplitude of seasonal variations in the atmospheric muon flux to a high degree of precision. MUTE is an open-source, publicly available program, providing a solid framework for accurate muon flux predictions in various underground environments, essential for applications in cosmic ray physics and dark matter searches.
Speaker: William Woodley (University of Alberta)
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22
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Neutrino Physics and Astrophysics: parallel session 1A North Hall #1
North Hall #1
Convener: William McDonough (Tohoku University)-
28
Latest KamLAND-Zen results and the impact of muon spallation on the 0𝜈𝛽𝛽 search
Neutrinoless double beta decay (0𝜈𝛽𝛽) is an extremely rare process that, if observed, would confirm the Majorana nature of neutrinos. KamLAND-Zen, an extension of the KamLAND neutrino detector in Japan using 136Xe dissolved in liquid scintillator, currently sets the most stringent limit on the 0𝜈𝛽𝛽 half-life of Xe-136. In this talk, I will present the latest KamLAND-Zen results, based on the complete dataset. A major challenge in this search arises from long-lived radioactive isotopes produced by muon spallation on xenon. This is possibly a limiting background, making precise tagging essential—not only for KamLAND-Zen, but also for next-generation detectors. I will discuss the current likelihood-based spallation tagging method, which relies on neutron captures correlated with the long-lived isotopes, and briefly introduce a machine learning approach using transformer models trained on FLUKA simulations. I will conclude with an update on KamLAND2-Zen, the ongoing upgrade that will extend the 0𝜈𝛽𝛽 search with improved background suppression and increased sensitivity.
Speaker: Kelly Weerman (Nikhef, University of Amsterdam) -
29
The CUORE experiment: current status and road ahead
After collecting more than five years of continuous data and accumulating over 2.8 tonne·years of TeO$_2$ exposure, CUORE has firmly established itself as a leading cryogenic calorimeter experiment for rare-event searches. We present a summary of our latest results which, along with our unprecedented cryogenic performance, demonstrate our readiness to tackle a different set of new challenges. After reaching our target exposure of 3 tonne·years TeO$_2$ in 2026, “CUORE Run-2” will follow a targeted cryogenic upgrade that will improve our low-energy analysis performance. We will describe how this initiative, associated analysis techniques, and results will largely benefit CUPID as the next-generation experiment continues to unlock the full potential of this detection technique.
Speaker: Alice Campani (Università degli studi di Genova - Istituto Nazionale di Fisica Nucleare sezione di Genova) -
30
Search for Neutrinoless Double-Beta Decay in $^{76}$Ge with the LEGEND experiment at Gran Sasso
The search for neutrinoless double beta 0νββ decay is considered as the only feasible way to prove the Majorana nature of neutrinos as well as to give indication on the mass hierarchy and on the absolute mass scale. Moreover, the discovery and observation of 0νββ decay would be the first indication of lepton number violation and have substantial repercussions on cosmology, giving a possible mechanism for matter-antimatter imbalance in the Universe.
The LEGEND project follows a phased approach to building a neutrinoless double beta decay experiment with discovery sensitiity for 0νββ in $^{76}$Ge at a half-life beyond $10^{28}$ years. The first phase, LEGEND-200, started taking data in 2023 with about 140 kg of Germanium detectors enriched in 76Ge. With an exposure of $1~\mbox{t}\cdot\mbox{yr}$ and a Background Index of $0.5~\mbox{cts}/(\mbox{FWHM}*\mbox{t}*\mbox{yr}) $, LEGEND-200 will be able to reach a sensitivity of about $10^{27}$ years. The next phase, called LEGEND-1000, will operate in LNGS with 1000 kg of $^{76}$Ge. The experiment design, which is informed by the results in LEGEND-200, will consist of 1 ton of $^{76}$Ge enriched Germanium detectors operated within an active liquid argon shield. The ultra-low background of LEGEND-1000 will allow the experiment to operate in the quasi-background free regime. This will result in an unprecedented sensitivity to 0νββ, sufficient to enable a discovery in the entire inverted neutrino mass ordering regime.Speaker: Alberto Garfagnini (Padova University and INFN-Padova) -
31
Status of the SuperNEMO Demonstrator and First Physics Data
SuperNEMO is a double-beta-decay experiment, whose isotope-agnostic tracker-calorimeter architecture has the unique ability to track trajectories and energies of individual particles. If the hypothesised lepton-number-violating process, neutrinoless double-beta decay (0νββ), is discovered, this full topological event reconstruction will be the only way to determine the mechanism. The detector serves as proof of concept for many novel developments in tracker-calorimeter technology, which could be used in a scaled-up version with neutrino-mass sensitivity comparable to next-generation experiments. In addition, the Demonstrator is uniquely positioned to make detailed studies of the Standard Model double-beta decay process (2νββ). Precise kinematic measurements of these events can place important constraints on nuclear models and the axial coupling constant, gA. Additionally, the Demonstrator can probe beyond-the-Standard-Model phenomena, including exotic 0νββ modes, Lorentz-violating decays, and bosonic neutrino processes. The SuperNEMO Demonstrator, located at LSM, France, is currently collecting double-beta-decay data from a 6.11kg Se-82 ββ source. First physics data and physics objectives will be presented.
Speaker: Xalbat Aguerre -
32
The CUPID neutrinoless double-beta decay experiment
Neutrinoless double-beta decay (0νββ) is a key process in addressing some of the most significant open questions in particle physics, namely the conservation of lepton number and the Majorana nature of the neutrino. Over the past decades, extensive efforts have been dedicated to improving the sensitivity of 0νββ half-life measurements across multiple isotopes. The next generation of experiments aims to probe half-lives greater than 10²⁷ years, reaching the sensitivity required to explore the Inverted-Ordering region of the neutrino mass spectrum.
Among the various techniques employed, low-temperature calorimetry has proven exceptionally promising and is expected to maintain a leading role in future searches, particularly through the CUPID experiment. CUPID (CUORE Upgrade with Particle IDentification) will search for the 0νββ decay of ¹⁰⁰Mo, leveraging the existing cryogenic infrastructure and expertise gained from CUORE, the first tonne-scale low-temperature calorimeter array, currently operating at the Laboratori Nazionali del Gran Sasso in Italy.
CUPID will utilize scintillating Li₂MoO₄ crystals enriched in ¹⁰⁰Mo, coupled with light detectors featuring Neganov-Trofimov-Luke amplification. With a total isotope mass of 240 kg, CUPID is designed to achieve a background index of 10⁻⁴ counts/keV/kg/year and a FWHM energy resolution of 5 keV. This performance will allow for a 3σ discovery sensitivity of 1.0 × 10²⁷ years after 10 live-years of data-taking, corresponding to an effective Majorana neutrino mass sensitivity in the range of 12–21 meV.
In this talk, we will present the current status of the CUPID experiment and outline the upcoming steps toward its construction.
Speaker: Irene Nutini (Istituto Nazionale di Fisica Nucleare - Milano Bicocca)
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28
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Neutrino Physics and Astrophysics: parallel session 1B North Hall #2
North Hall #2
Convener: Thomas Schwetz-Mangold-
33
Double Chooz Single-Detector Physics Results
The Double Chooz experiment, located near the Chooz Nuclear Power Plant (France), has provided precise measurements of the neutrino mixing angle θ13 through the detection of antineutrinos from reactor cores. This multi-detector experiment, comprising a far detector located approximately 1050 metres from the reactors and a near detector at about 400 metres, was designed to minimise systematic uncertainties by comparing the antineutrino flux and energy spectra at the two locations for high-precision neutrino oscillation characterisation. However, each detector can also work independently to measure the absolute reactor flux with leading precision too. This contribution will present the latest results released, referred to as DC-V, focusing on the Single Detector (or SD) analyses using the full dataset presented here for the first time. This is expected to be the last data release of the experiment.
Speaker: Philipp Soldin (RWTH Aachen University) -
34
Recent Results from MicroBooNE's Search for a Low-Energy-Excess Anomaly under the Electron Hypothesis and additional BSM Studies
The MicroBooNE experiment utilizes an 85-tonne active mass liquid argon time projection chamber neutrino detector. It can distinguish between photon and electron electromagnetic showers and select charged-current electron neutrino and muon neutrino events with exceptional performance. In this talk, we will present new results on MicroBooNE's investigation of the MiniBooNE Low Energy Excess under the electron hypothesis. These results are based on the complete dataset collected over the experiment's five years of operation. This measurement excludes an electron-like interpretation of MiniBooNE's excess at above 99% CL. Additionally, we will present our progress in searching for eV-scale sterile neutrinos in the 3+1 oscillation framework. This effort leverages the well-understood charged-current electron neutrino and muon neutrino event selections and utilizes neutrinos from both the on-axis Booster Neutrino Beam and the off-axis Neutrino from the Main Injector beam. This enables us to test the sterile neutrino hypothesis, probing the parameter space that is compatible with short baseline anomalies from the LSND, MiniBooNE, Neutrino-4, Gallium, and BEST experiments. Finally, we will present other BSM searches, including searches for heavy neutral leptons and Higgs portal scalars using MicroBooNE data.
Speaker: Xiangpan Ji (Nankai University) -
35
New results from MicroBooNE's search for a Low-Energy-Excess anomaly in the photon and e+e- channels
The MicroBooNE experiment is an 85-ton active mass liquid argon time projection chamber (LArTPC) neutrino detector situated in the Fermilab Booster Neutrino Beam (BNB). In this talk, we will present several new results of the experiment's investigations of the MiniBooNE Low Energy Excess in both the single-photon and electron-positron channels, probing the Standard Model background interpretation as well as Beyond the Standard Model (BSM) explanations beyond 3+1 oscillations. For the photon channel, we performed a model-independent, inclusive search for events with photon showers. While data and predictions agree across the full signal region, a 2σ excess is observed in the subset of events with no visible protons in the final state. Additionally, searches for single photon production from neutral-current coherent-like processes as well as an updated result from Delta radiative decay will be presented. In the electron-positron channel, we conduct the first direct test of dark sector models in which dark neutrinos, produced via neutrino-induced scattering, decay into visible a e+e- pair and missing energy. The resulting constraints on these models as explanations for the MiniBooNE anomaly will be discussed.
Speaker: Xiao Luo (University of California Santa Barbara) -
36
The latest reactor neutrino oscillation results and reactor neutrino flux and spectrum measurement results from Daya Bay
The Daya Bay reactor neutrino experiment, pioneering the measurement of a non-zero value for the neutrino mixing angle θ13 in 2012, operated for about nine years from Nov. 24, 2011, to Dec. 12, 2020. Antineutrinos emanating from six reactors with a thermal power of 2.9 GWth were detected by eight identically designed detectors, which were positioned in two near and one far underground experimental halls. This spatial configuration, spanning kilometer-scale baselines between detectors and reactors, facilitates a precise determination of the relative difference of the neutrino event rates and spectra among detectors. The statistical power and well-understood systematics also enable a precise determination of the absolute reactor neutrino flux and spectrum. The collaborators continue to develop new analysis techniques and search for the potential of the experiments. This talk will show the measurements of θ13 and the mass-squared difference by utilizing the neutron Gd-capture and H-capture tagged sample under the three-neutrino mixing framework. The talk will also present the crucial measurements of the total reactor neutrino flux and spectrum, as well as the results for the U-235 and Pu-239 components.
Speaker: Zhe Wang (Tsinghua University) -
37
Precision Neutrino Physics: Status and Outlook in the 3ν Paradigm
We present an updated global analysis of the standard three-neutrino (3ν) framework, incorporating the latest oscillation and nonoscillation data available at the start of 2025. Notably, we report subpercent-level precision in the determination of the atmospheric mass-squared splitting, marking a significant milestone in neutrino oscillation physics. Our analysis reveals evolving constraints on the mass ordering, the CP-violating phase, and the θ23 octant, though current hints remain statistically inconclusive. Beyond oscillations, we update bounds on absolute neutrino mass observables from β-decay, neutrinoless double β-decay, and cosmology, with recent data pointing to potential tensions or novel physics within the ΛCDM paradigm. Looking forward, we highlight the pivotal role of the JUNO experiment, which is poised to deliver high-precision measurements of key oscillation parameters and provide an independent handle on the mass ordering. As the field transitions into the era of subpercent precision, resolving current ambiguities and ensuring robust control over shared systematics across experiments will be critical. These advances promise to deepen our understanding of the neutrino sector and may unveil new directions in particle physics and cosmology.
Speaker: Antonio Marrone (University of Bari, Italy)
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33
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Underground Laboratories: parallel session 1 North Hall #3
North Hall #3
Convener: Sean Paling-
38
The status and prospect of CJPL
Since 2020, the Jinping Underground Laboratory has started a new construction. After 5 years of hard work, the construction of the project has been almost completely completed so far. Construction of a new low-background measurement and analysis center has also been completed. In this report, we will introduce the material screening during construction, underground indoor radiation environment, control and effect of radon concentration in the indoor-air, and the characteristics of various shielding devices. In addition, based on the new underground experimental environment, we will show some other physics experiments and their unexpected results.
Speaker: Zhi Zeng (Tsinghua University) -
39
Status of the Yemilab operation
The Yemilab, a new deep underground laboratory, has been constructed to be located under the Yemi mountain at Jeongseon in Korea. The overburden is 1,000 m from the top of the Yemi mountain, and the laboratory space is approximately 25,000 m3. We can access the laboratory using a cage that has a 4 m/s vertical speed through the 600 m shaft and electric vehicles as transportation through the 800 m tunnel. The electricity, mobile networks, and safety facilities have been prepared and operating smoothly since the end of 2022.
Two major experiments, AMoRE-II to search for a neutrinoless double beta decay of 100Mo and COSINE to search for a WIMP as a strong dark matter candidate, are preparing to start the initial operation soon. Even more, various tabletop scale experiments have been prepared to open chances to be a large-scale experiment in the future, such as positronium, astrophysical S-factor, and further detector R&D programs to search for a rare decay.
We introduce seasonal radioactive environmental conditions (especially the Radon level) for rare event search experiments, and support facilities for wide applications at Yemilab.Speaker: Jungho So (Institute for Basic Science) -
40
The Piedicastello Tunnels: a Potential Underground Laboratory for Astroparticle Physics in Trento, Italy
In the fields of astroparticle physics, nuclear astrophysics, and quantum computing, the identification of underground laboratories with suppressed cosmogenic backgrounds is of critical importance.
Located approximately 500 meters from the center of Trento, Italy, the Piedicastello tunnels lie beneath 100 meters of limestone rock from the Doss Trento hill. The site covers over 6,000 square meters and is currently used for events, temporary exhibitions, and educational activities.
A measurement campaign was conducted to characterize the gamma and muon backgrounds at various locations within the tunnels, employing NaI(Tl), CZT, and plastic scintillator detectors. In the deepest section, the muon flux was found to be approximately two orders of magnitude lower than at the surface, and a total gamma flux of about 2cm⁻²s⁻¹ was measured.
In addition, several samples of rock, concrete, dust, and wall paintings, collected from the tunnel, were analyzed using a high-purity germanium spectrometer to identify major radioactive contaminants.
These results indicate that the Piedicastello tunnels could be a promising candidate for hosting facilities requiring low environmental background conditions.Speaker: Francesco Nozzoli (Trento University & INFN-TIFPA) -
41
A new HPGe spectrometer with μBq/kg sensitivity for sample analysis
A new HPGe spectrometer with $\mu$Bq/kg sensitivity for sample analysis.
G. Zuzel, A. Biondi, C.P. Garay+
*) M. Smoluchowski Institute of Physics, Jagiellonian University, Krakow, Poland
+) Laboratorio Subterráneo de Canfranc, Canfranc, Spain
Low-level gamma spectroscopy with High Purity Germanium (HPGe) detectors has become an essential tool for material screening in rare event physics experiments. These demand lowest possible radioactivity concentrations near their target or detector array. Typical examples are searches for solar neutrinos, neutrinoless double beta decay and dark matter.
A new HPGe spectrometer, called GeRysy, has been installed in Hall C of the underground laboratory at Canfranc (LSC). It is based on a 2.3 kg germanium crystal and fabricated in the SAGe-well geometry by Canberra. The design of the detector and its cryostat was highly customized. It was placed in a dedicated multi-layer shield to eliminate the influence of local gamma radiation on the background. The materials used to fabricate the shield components (copper, lead of various qualities) were carefully selected with respect to radio-purity. Radon impact is suppressed by flushing the shield either by Rn-free air available at LSC, or by nitrogen gas.
After several test measurements we conclude that we have reached very low level of background, which makes possible measurements with sensitivities down to single $\mu$Bq/kg (1 ppt U/Th equivalent) for various samples. This makes GeRysy one of the most sensitive gamma spectrometer world-wide. Construction of the detector, background analysis and selected results obtained for various samples will be discussed. A prospect for installation of further detectors at LSC will be outlined
Speaker: Alex Biondi (Jagiellonian University in Krakow) -
42
About Hamamatsu
In this talk, we’ll talk about the general information of Hamamatsu, introduce PMT examples which is mainly used for Astroparticle and Underground Physics experiment and latest developmental situation of SiPM.
Speaker: Kensuke Suzuki
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38
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Coffee break International Conference Center
International Conference Center
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Cosmology and Particle Physics: parallel session 2 Conference Room F1-R3
Conference Room F1-R3
Convener: Jun Zhang (University of Chinese Academy of Sciences)-
43
Determining properties of dark matter by astronomical observations
We show how the astronomical observations of dwarf galaxies give strong constraints on the properties of dark matter. Some dwarf galaxies prefer a wave like dark matter or self-interacting dark matter.
Speaker: Xiaojun Bi -
44
Dark photon dark matter from flattened axion potentials
Dark photons can be resonantly produced in the early universe via their coupling to an oscillating axion field. However, this mechanism typically requires large axion–dark photon couplings or some level of fine-tuning. In this talk, I will present a new scenario in which efficient dark photon production arises from axion potentials shallower than quadratic. For moderately large initial misalignment values, the axion field can undergo either strong self-resonance or efficient dark photon production with $\gtrsim \mathcal{O}(1)$ couplings. When self-resonance dominates and disrupts the field’s homogeneity, we show that oscillons naturally form and can sustain continued dark photon production. If the dark photon mass lies within three orders of magnitude below the axion mass, the resulting abundance can constitute a significant fraction of the present-day dark matter. We support this scenario with numerical lattice simulations of a benchmark model. Our results further motivate experimental searches for ultralight dark photon dark matter.
Speaker: Hong-Yi Zhang (Tsung-Dao Lee Institute, Shanghai Jiao Tong University) -
45
Constraining Pressure-Based Dark Energy Models with Latest Cosmological Data
In this talk, I explore an extension of the standard cosmological model by introducing a dynamical dark energy (DDE) scenario, where the pressure evolves with cosmic time. Instead of assuming a constant dark energy component, we expand the pressure around the present epoch to capture possible deviations from a cosmological constant. This approach introduces one or two new parameters, depending on the order of the expansion, which quantify how dark energy evolves over time. Using recent observational data, including Planck CMB, DESI galaxy clustering, and DESY5 supernovae, I present constraints on both first- and second-order DDE models. The results show significant evidence for dynamical behavior: a 2.7σ preference for the first-order model and over 4σ for the second-order case. In particular, the second-order reconstruction reveals a non-monotonic evolution of dark energy, including phantom-crossing behavior. Importantly, the inferred trends are consistent across datasets and align well with other dynamical parametrizations, stressing the robustness of this pressure-based framework. Based on arXiv 2505.02932.
Speaker: Hanyu Cheng (Tsung Dao Lee institute & SJTU)
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43
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Dark Matter and Its Detection: parallel session 2A Conference Room F2-R1
Conference Room F2-R1
Convener: Roberto Santorelli (CIEMAT)-
46
General overview of the DarkSide-20k experiemnt at LNGS: status and goals
DarkSide-20k is an experiment aimed at the direct detection of Weakly Interacting Massive Particle dark matter. Currently under construction at the Laboratori Nazionali del Gran Sasso (LNGS) of the INFN in Italy, the experiment utilizes a 50-tonne dual-phase Liquid Argon TPC. This TPC employs underground, low-radioactivity argon and is surrounded by two active veto systems, all housed within a proto-DUNE-like membrane cryostat.
Although certain components, such as the membrane cryostat, have already been produced and installed, the construction of the experiment continues to face several technical challenges. These include assembling and testing 20 m$^2$ of cryogenic SiPMs into readout modules, the construction of a fully acrylic-based TPC, and the development of industrial-scale facilities for the extraction, purification, and testing of underground argon.
A few prototypes are currently being tested at LNGS and at the University and INFN of Naples to validate the technical solutions.
The experiment is anticipated to achieve world-class sensitivity in the search for both high- and low-mass WIMP dark matter and the detection of supernova neutrinos.Speaker: Walter Bonivento (INFN Cagliari) -
47
Dark Matter Search in DEAP-3600: Recent Results and Future Prospects
DEAP-3600, featuring a 3.3-tonne liquid argon target, is a dark matter direct detection experiment located at SNOLAB in Sudbury, Canada. Since 2019, it has set the most stringent exclusion limit in argon for Weakly Interacting Massive Particles (WIMPs) above 20 GeV/c².
Building on its established analyses, the experiment has broadened its physics scope to include MeV-scale recoil energies, achieving world-leading exclusion limits for ultra-heavy, multi-scattering dark matter candidates. It has also initiated the first-ever search for neutrino absorption interactions in argon, an investigation still in progress. Furthermore, DEAP-3600 is advancing a detailed Profile Likelihood Ratio WIMP analysis on its complete second run, targeting unprecedented sensitivity. This progress draws on the understanding of dominant backgrounds, including shadowed alpha particles and dust within the detector. These challenges have driven detector upgrades for the upcoming third fill, scheduled for this year, with cooling initiated in March 2025.
Additionally, DEAP-3600's tonne-scale target mass has enabled significant insights into argon properties. This includes achieving the most precise measurement of argon's specific activity to date, determined to be 0.964 ± 0.024 Bq/kg of atmospheric argon. The experiment has also advanced quenching factor modeling for alpha particles down to 10 keV, with further local R&D measurements planned to constrain low-energy uncertainties.
The remarkable position resolution in its single-phase chamber, combined with the extended physics program at MeV scales and the results from the forthcoming third fill, is poised to significantly influence the physics reach and design of ARGO. ARGO, a pivotal step in the Global Argon Dark Matter Collaboration, will feature a 300-tonne fiducial ultra-pure argon mass as the ultimate liquid argon experiment searching for WIMPs, diving into the neutrino fog.
Speaker: Shawn Westerdale (University of California, Riverside) -
48
ALETHEIA: Hunting for low-mass dark matter with liquid helium-filled TPCs
The evidence of dark matter from astrophysics and cosmology is overwhelmingly robust, yet the evidence of dark matter from particle physics is continuously null. ALETHEIA aims to hunt for low-mass dark matter with liquid helium-filled TPCs. Thanks to such unique advantages as (a) ease to purify, (b) no radioactive isotopes, and (c) potentially strong ER/NR discrimination, liquid helium-filled TPCs would achieve especially low backgrounds. As a result, 1 ton*yr ALETHEIA data is supposed to reach the B-8 neutrino floor/fog cross-section, or 10^{-45} cm^2. In this talk, I will present the R&D progress we have made in the past five years or so, which demonstrate that a single-phase liquid helium TPC is technologically viable. Research on a dual-phase TPC is currently underway.
Speaker: Liao Junhui -
49
The SABRE South Experiment at the Stawell Underground Physics Laboratory
SABRE is an international collaboration that will operate similar particle de-
tectors in the Northern (SABRE North) and Southern Hemispheres (SABRE
South). This innovative approach distinguishes possible dark matter signals
from seasonal backgrounds, a pioneering strategy only possible with a southern
hemisphere experiment. SABRE South is located at the Stawell Underground
Physics Laboratory (SUPL), in regional Victoria, Australia.
SUPL is a newly built facility located 1024 m underground (∼2900 m water
equivalent) within the Stawell Gold Mine and its construction has been com-
pleted in 2023.
SABRE South employs ultra-high purity NaI(Tl) crystals immersed in a Linear
Alkyl Benzene (LAB) based liquid scintillator veto, enveloped by passive steel
and polyethylene shielding alongside a plastic scintillator muon veto. Signifi-
cant progress has been made in the procurement, testing, and preparation of
equipment for installation of SABRE South. The SABRE South muon detector
and the data acquisition systems are actively collecting data at SUPL and the
SABRE South’s commissioning is planned to be completed by the end of 2025.
This presentation will provide an update on the overall progress of the SABRE
South construction, its anticipated performance, and its potential physics reach.Speaker: Suerfu Burkhant (High Energy Accelerator Research Organization (KEK)) -
50
The SABRE North project at Gran Sasso Laboratory
The SABRE experiment aims to deploy arrays of ultra-low-background NaI(Tl) crystals to carry out a model-independent search for dark matter through the annual modulation signature. SABRE will be a double-site experiment, consisting of two separate detectors in the two terrestrial hemispheres.
The SABRE North detector will be installed underground at LNGS and will deploy an array of 9 ultra-high radio-purity NaI(Tl) detectors (5 kg mass each) in a Cu and PE passive shielding.
The expected background rate in the ROI [1,6] keV is of order 0.5 dru. To this end SABRE North will make use of zone refining purification of the NaI powder. The collaboration has recently confirmed by means of several tests the technology to produce 5 kg size NaI(Tl) crystals after zone refining purification. This is a breakthrough in the production of ultra-high radio-purity NaI(Tl) scintillators. Based on this development SABRE North is starting crystal production. The first crystal after zone refining is expected to be produced and delivered to LNGS in 2025 for characterization.
Results from zone refining runs and crystal growth development will be reported.Speaker: Krzysztof Szczepaniec (I.N.F.N. Laboratori Nazionali del Gran Sasso) -
51
Recent Results from the COSINE-100 Experiment
COSINE-100 is a direct detection experiment designed to test the DAMA/LIBRA collaboration's claim of observing an annual modulation signal attributed to dark matter interactions using NaI(Tl) crystals. From September 2016 to March 2023, COSINE-100 collected data with a 106 kg NaI(Tl) detector array at the Yangyang Underground Laboratory in Korea.
Several dark matter search analyses were conducted with a 1 keV energy threshold, including both model-dependent and model-independent tests of DAMA-like signals. In this presentation, we report updated results from physics analyses using an improved 0.7 keV energy threshold, including a comprehensive annual modulation search based on the full 6.4-year dataset.
Speaker: Insoo Lee (Institute for basic science) -
52
Strong Constraints on the DAMA/LIBRA Modulation Signal from ANAIS-112
For over two decades, the DAMA/LIBRA experiment has reported an annual modulation in the low-energy region, consistent with the expectation from dark matter (DM) in the galactic halo due to Earth's motion around the Sun. For most WIMP candidates, this result is excluded by the null results of other experiments, making it one of the most puzzling anomalies in the field. However, such comparisons are model-dependent,
as these experiments use different target materials with respect to DAMA/LIBRA (NaI(Tl) scintillators).
In recent years, the ANAIS-112 and COSINE-100 experiments, which also employ NaI(Tl) detectors, have obtained results that are incompatible with those of DAMA/LIBRA at a high confidence level, leaving little room for a DM interpretation of the observed modulation.
The ANAIS-112 experiment uses 112.5 kg of NaI(Tl) detectors at the Canfranc Underground Laboratory and it has been taking data since August 2017. In this talk we will present the results of the annual modulation analysis corresponding to six years of ANAIS–112 data, that are the most sensitive to date with the same target material. Results are incompatible with the DM interpretation of the DAMA/LIBRA modulation signal at a 4$\sigma$ confidence level.
We will also review the systematic uncertainties affecting the comparison, particularly those related to the response of detectors to nuclear recoils.Speaker: Maria Martinez (CAPA-Universidad de Zaragoza)
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46
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Dark Matter and Its Detection: parallel session 2B Conference Room F2-R2
Conference Room F2-R2
Convener: wei chao-
53
Constraints on Strongly-Interacting Dark Matter from the James Webb Space Telescope
Direct detection searches for dark matter are insensitive to dark matter particles that have large interactions with ordinary matter, which are stopped in the atmosphere or the Earth’s crust before reaching terrestrial detectors. We use “dark” calibration images from the James Webb Space Telescope to derive novel constraints on sub-GeV dark matter candidates that scatter off electrons. In this talk, I will show that for a 0.4% subcomponent of dark matter that interacts with an ultralight dark photon, we disfavor all previously allowed parameter space at high cross sections, and constrain some parameter regions for subcomponent fractions as low as ∼0.01%.
Speaker: Peizhi Du (University of Science and Technology of China) -
54
Illuminating Very Heavy Dark Matter in the Earth with Tau Neutrinos
Dark matter accumulates inside Earth as the planet plows through the dark matter halo in the Milky Way. Possible annihilation of dark matter to Standard Model particles can be probed in indirect dark matter searches. Among the messengers, neutrinos are uniquely ideal as they can escape dense regions. Neutrino telescopes offer opportunities to search for dark matter signals from the Earth. Such studies have been restricted to dark matter masses below PeV as the Earth becomes opaque to very-high-energy neutrinos. However, the tau regeneration effect enables very-high-energy tau neutrinos to traverse the Earth and regenerate at lower energies, resulting in a detectable signal. In this talk, I will discuss utilizing neutrino telescopes operating at TeV-PeV energies to probe very heavy dark matter and present upper limits on the spin-independent dark matter–nucleon cross section derived from IceCube public data.
Speaker: Qinrui Liu (Queen's University) -
55
Boosted dark matter from semi-annihilations in the galactic center
In some scenarios, the dark matter relic abundance is set by the semi-annihilation of two dark matter particles into one dark matter particle and one Standard Model particle. These semi-annihilations might still be occurring today in the Galactic Center at a significant rate, generating a flux of boosted dark matter particles. We investigate the possible signals of this flux component in direct detection and neutrino experiments for sub-GeV dark matter masses. We show that for typical values of the semi-annihilation cross-section, the sensitivity of current experiments to the spin-independent dark matter-proton scattering cross-section can be several orders of magnitude larger than current constraints from cosmic-ray boosted dark matter. We also argue that the upcoming DARWIN and DUNE experiments may probe scattering cross-sections as low as 10−37cm2 for masses between 30 MeV and 1 GeV.
Speaker: Takashi Toma (Kanazawa University) -
56
Probing MeV Dark Matter Via Solar Reflection
Solar reflected dark matter refers to dark matter particles reflected and accelerated by the high energy electrons in solar interior. This process can boost MeV dark matter energies, enhancing potential signals in direct detection experiments. Extending this idea, we demonstrate that in detectors composed of single crystals such as silicon or germanium, the collision rate and energy deposition are influenced by the angle between the momentum of the incoming DM and the orientations of the crystallographic axes. This results in a daily modulation of the signal. On the other hand, we also explore the scenario of inelastic dark matter, where scattering within the Sun promotes dark matter to an excited state. Subsequent de-excitation in ground-based detectors releases additional energy, significantly enhancing the detection signature of dark matter with mass larger than electron mass.
Speaker: Mr Haoming Nie (Tsinghua University) -
57
Boosted Dark Matter Directionality in Large Liquid Scintillators
We propose detecting dark matter by using neutron capture events induced by Cosmic-Ray Boosted Dark Matter (BDM)-nucleon scattering. This approach leverages the directional preference of BDM originating from the Galactic Centre to suppress the background. We demonstrate that it is possible to statistically reconstruct the BDM direction through neutron capture events. Large liquid scintillator detectors with excellent energy and vertex resolution are well-suited for this approach. By incorporating directionality reconstruction, this method can improve constraints on DM-nucleon interactions.
Speaker: Mr Samuel S.H. Tse (The Chinese University of Hong Kong) -
58
Many-body atomic response functions for sub-GeV dark matter-electron interactions
Direct searches of sub-GeV light dark matter (LDM) in our galaxy
through its interactions with electrons has been a rapidly-growing
area. As the kinetic energy of such a LDM particle is generally below
keV, its scattering triggers sub-keV electronic recoils in detectors,
and a proper understanding of these events usually requires reliable
many-body theory inputs.In this talk, we present a comprehensive data set of atomic response
functions for xenon and germanium with 12.2 and 80 eV energy
thresholds, respectively. Our approach, the multiconfiguration
relativistic random phase approximation, takes into account the
relativistic, exchange, and correlation effects in one self-consistent
framework; and is benchmarked by photoabsorption data from thresholds
to 30 keV with errors less than 5%. The significance of these effects
and the importance of the benchmark will be discussed.Speaker: Prof. Cheng-Pang Liu (National Dong Hwa University)
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53
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High-Energy Astrophysics and Cosmic Rays: parallel session 2 Conference Room F1-R2
Conference Room F1-R2
Convener: min zha-
59
Recent Highlights from the Telescope Array
The Telescope Array (TA) is the largest observatory for ultra-high-energy cosmic rays (UHECRs) in the Northern Hemisphere. It investigates extensive air showers (EAS) produced by cosmic rays with energies ranging from 10^{15} eV to 10^{21} eV, using a hybrid detection system. This system includes a surface array of scintillator detectors that sample the footprint of air showers at ground level, and fluorescence telescopes that observe the ultraviolet light emitted by EAS in the atmosphere. To improve statistics at the highest energies, the TA collaboration is expanding its capabilities with the TAx4 project, which has already added new telescopes and is working to quadruple the surface detector area. Additionally, the deployment of TALE infill surface detectors has extended the energy range of hybrid observations to lower energies. We present the current status of the experiment along with recent results on the UHECR energy spectrum, composition, and anisotropy. These include the observation of a new spectral feature around 10^{19.2} eV and updated measurements of anisotropy in UHECR arrival directions.
Speaker: Eiji Kido (Institute for Cosmic Ray Research, University of Tokyo) -
60
25 Years of the Pierre Auger Observatory: A Constantly Evolving Instrument Yielding a Rich and Varied Harvest
In 2001, the first water-Cherenkov detector of what would become the Pierre Auger Observatory was installed in the Pampa Amarilla, Argentina. Since then—almost 25 years later—the Observatory has not only been completed and operational since 2004, but has also continually evolved in its instrumentation, results, and scientific scope.
Originally designed to study cosmic rays with energies above $10^{18}$ eV, comprising two main components—an extensive air shower array covering 3000 km$^2$ and a set of 24 fluorescence telescopes—, it has since developed into a multi-energy, multi-detector facility. The Observatory has been augmented with additional instruments: two smaller and denser arrays and one more fluorescence detector to extend the energy range down to $10^{16}$ eV, along with arrays of radio antennas and scintillators—some of them underground—to enhance shower measurements, particularly for characterizing the nature of the primary cosmic particles.
This wealth of instrumentation, along with growing data sets and improved control of systematics, has enabled landmark discoveries in the field of ultra-high-energy cosmic rays. These include the detection of a dipolar anisotropy in the arrival directions of the highest-energy cosmic rays, an unexpected complexity in the suppression at the end of the energy spectrum, and an equally unexpected evolution of cosmic-ray mass with energy. Over the past 25 years, the Observatory has broadened its scientific reach, contributing to the emerging fields of multimessenger astronomy and open science, playing a role in hadronic and particle physics by probing high-energy interactions beyond the LHC’s reach, and expanding into geophysics—particularly atmospheric electricity—and heliospheric and solar physics.
In this presentation, we will offer an overview of the Observatory’s rich and varied scientific harvest, highlighting not only the evolution of its instrumentation and contributions to our understanding of ultra-high-energy cosmic rays—its foundational field—but also its expansion, and results, into other scientific domains.Speaker: Piera Luisa Ghia (IJCLab, IN2P3/CNRS) -
61
Measurement of the cosmic ray Proton and Helium spectrum with energy from tens of TeV to 1PeV by LHAASO
One of the scientific goals of LHAASO is to accurately measure the spectrum of cosmic rays composition, build a bridge between space-based and ground-based experiments, and propose limitations on the origin, acceleration, and propagation mechanisms of cosmic rays. LHAASO experiment measured the proton and helium energy spectrum near the “knee” region, starting the measurements from 150 TeV. Here, we use the near-vertical events of the LHAASO experiment to measure the proton and helium energy spectrum from tens of TeV to 1PeV. This promises to establish a connection between space-based and ground-based experiments, achieving continuous and coherent energy spectrum measurements, and help clarify the absolute energy scale of cosmic rays.
Speaker: Suhong Chen (Institute of High Energy Physics, CAS) -
62
Origin of PeV Cosmic Rays
In light of LHAASO observations of ultra-high energy gamma-ray emission and measurement of cosmic ray spectra, I will discuss their implications on the origin of PeV cosmic rays.
Speaker: Prof. Siming Liu (西南交通大学) -
63
Astrophysical interpretation of ultra-high-energy cosmic ray measurements at the Pierre Auger Observatory
The Pierre Auger Observatory measures several characteristics of ultra-high-energy cosmic rays (UHECRs), in particular their energies, the shower maximum depths $X_\mathrm{max}$ of the air-shower profiles, and the arrival directions. Using the energy spectrum and the distributions of $X_\mathrm{max}$ in a combined fit, the parameters of homogeneously distributed UHECR sources can be constrained. We find that the data at the highest energies are well reproduced by an extragalactic source population dominating above the ankle that emits a mixed composition with a hard spectrum. Below the ankle, another light extragalactic population as well as a subdominant Galactic contribution is needed to explain the data.
In the case of very strong extragalactic magnetic fields between the closest sources and Earth, the spectral index of the high-energy population can be much softer and even in agreement with the expectations from shock acceleration. When taking into account also the arrival directions, it is revealed that adding a population of nearby starburst galaxies to the homogeneous background leads to an improvement of the model likelihood on the 4.5 sigma significance level. The energy-dependency of the arrival directions at the highest energies is well described by the modeled contribution from the starburst catalog or by that of the nearby radio galaxy Centaurus A.Speaker: Teresa Bister (Nikhef / Radboud University) -
64
Probing the Flux of Ultra-High-Energy Neutral Particles at the Pierre Auger Observatory
The Pierre Auger Observatory, the largest facility for detecting ultra-high-energy cosmic rays (UHECRs), enables detailed studies of extensive air showers over a wide energy range, from 50 PeV up to and beyond 100 EeV. Its hybrid design, combining a surface detector array, fluorescence detector, and underground muon detectors, allows the reconstruction of shower properties with high precision. This makes it possible to search for rare signatures of neutral particles such as photons and neutrinos, despite the overwhelming background from hadronic cosmic rays. Ultra-high-energy photons and neutrinos are expected as secondary products in interactions of UHECRs with background radiation, and possibly also from top-down scenarios such as the decay of super-heavy dark matter. In this contribution, we present results from a variety of searches based on 20 years of Phase I data. These include diffuse flux searches, directional searches toward candidate astrophysical sources, and investigations of transient events. The analyses employ both hybrid techniques, combining data from multiple detector systems, and searches using only the surface detector array to exploit its large exposure at the highest energies. To date, there has not yet been a statistically significant detection of photon- or neutrino-induced showers. Consequently, upper limits on their fluxes place strong constraints on models of cosmic-ray origin, source evolution, and scenarios involving exotic physics such as dark matter decay.
Speaker: Fiona Ellwanger (Karlsruhe Institute of Technology)
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59
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Neutrino Physics and Astrophysics: parallel session 2A North Hall #1
North Hall #1
Convener: Yury Kolomensky-
65
Search for Neutrinoless Double-Beta Decay of Xe-136 with the PandaX-4T Detector
The search for neutrinoless double-beta decay (NLDBD) provides insights to the Majorana or Dirac nature of neutrinos, as well as their mass. PandaX-4T experiment, located at the China Jinping Underground Laboratory, uses a dual-phase xenon time projection chamber with 3.7-tonne natural xenon (8.9% Xe-136 abundance) in the sensitive volume. In this talk, I will present the optimization of data processing and background modeling in the MeV energy region of PandaX-4T, and report the latest results of Xe-136 NLDBD search based on dataset from the commissioning run and the first science run. It represents the most stringent constraint from a natural xenon detector to date.
Speaker: 澍 张 (中山大学) -
66
Design and prospect of the CDEX-300 neutrinoless double beta decay experiment
The CDEX-300 is a next generation neutrinoless double beta (0$\nu\beta\beta$) decay experiment based in China Jinping underground laboratory (CJPL). CDEX-300 aims at searching the 0$\nu\beta\beta$ decay of Ge-76 in the inverted neutrino mass hierarchy using high purity germanium (HPGe) detectors. We propose to build a 200 kg HPGe array with 2.5 keV (FWHM) energy resolution and 1E-4 cts/keV/kg/yr background level in the 2039 keV signal region. CDEX-300 is projected to achieve a $1.92\times10^{27}$ yr Ge-76 0$\nu\beta\beta$ half-life 3$\sigma$ discovery sensitivity with a 10-yr operation. This report will outline the experimental design, background control technologies, and the physical potential of the CDEX-300.
Speaker: Wenhan Dai (Tsinghua University) -
67
AMoRE-II construction status
The AMoRE experiment has been searching for neutrinoless double beta decay in Mo-100 nuclei, setting the most stringent limit to date on the half-life of the decay as larger than 2.9 x 10^24 years at 90% CL. The experiment is now advancing toward the AMoRE-II phase, which aims for a sensitivity of 4.5 x 10^26 years, utilizing a large cryogenic calorimeter array with lithium molybdate crystals embedded with approximately 90 kg of the Mo-100 isotope, and targeting a background level of 10^-4 counts/keV/kg/year in the region of interest around the 3034 keV Q-value. The detector housing, including the radiation shield and muon veto system, is already in place and undergoing commissioning at Yemilab. The detector array will be constructed in two stages: stage 1 with 27 kg of detector mass, and stage 2 with a total of 157 kg. The construction of stage 1 is expected to be completed later this year, opening up new scientific opportunities with significantly enhanced sensitivity. The status and prospects of the AMoRE-II experiment will be discussed in the presentation.
Speaker: SeungCheon Kim (CUP, IBS) -
68
R&D program for neutrinoless double beta decay search at JUNO
The search for neutrinoless double beta decay (0vbb) is one of the most important topics in neutrino physics. Multiple next generation ton-scale experiments are planned worldwide with sensitivities to effective Majorana neutrino mass covering the entire inverted mass ordering phase space. A multi-isotope campaign around the world is also necessary for an unambiguous discovery for this rare process. Jiangmen Underground Neutrino Observatory (JUNO) is a multipurpose neutrino observatory featuring 20 kton liquid scintillator (LS) as the target medium with the main purpose of determining the neutrino mass ordering with reactor neutrinos. The detector construction was completed at the end of 2024. It is currently being filled with liquid scintillator, and the process is expected to conclude by this summer. Thanks to its large target mass, low background and good energy resolution, JUNO has great potential to be upgraded to search for 0vbb by loading isotope to the LS. JUNO collaborators are carrying out R&D on loading 0vbb isotope to LS, developing purification methods and advanced analysis techniques for suppressing backgrounds. In this talk, we shall cover the R&D status for these aspects and the 0vbb search prospective with the JUNO upgrade.
Speaker: Gaosong Li -
69
AXEL: high-pressure Xe gas TPC for neutrinoless double beta decay search
A Xenon ElectroLuminescence (AXEL) experiment aims to search for neutrinoless double beta decay (0$\nu\beta\beta$) using a high-pressure xenon gas time projection chamber. We have developed a novel ionization-electron counter called Electroluminescence Light Collection Cell (ELCC), which enables to achieve excellent scalability and background rejection with track patterns and superior energy resolution. Performance of the detector has been demonstrated using a 180L-size prototype. A dedicated Cockcroft-Walton high-voltage generator was installed inside the chamber and successfully applied up to –34.3 kV in 6.8 bar of xenon gas. The obtained energy spectrum exhibited numerous sharp peaks, achieving an energy resolution of (0.67$\pm$0.08) % FWHM at 2615 keV. Furthermore, three-dimensional electron tracks were successfully reconstructed, and evaluation of background rejection with machine-learning based technique is ongoing using the obtained tracks. To improve track clarity, the Richardson-Lucy deconvolution method is under development. Toward the first 0$\nu\beta\beta$ search with the AXEL detector, a 1000L-size detector is in construction, and R&D efforts are underway on several key components, including high-voltage generation up to –76.4 kV using the Cockcroft-Walton generator, large-area silicon photomultiplier for the ELCC, low-radioactivity connector for signal transfer, dedicated readout electronics, and efficient scintillation light detector.
Speaker: Junya Hikida (Kyoto university) -
70
Toward a background-free ton-scale $0\nu\beta\beta$ bolometric experiment: Status and Prospects of BINGO
BINGO is a technology demonstrator dedicated to the development of innovative background reduction techniques for cryogenic calorimetric searches for neutrinoless double beta decay ($0\nu\beta\beta$). Targeting a background index of $10^{-5}$ counts/(keV·kg·yr), BINGO aims to establish a path toward a nearly background-free $0\nu\beta\beta$ experiment based on a tonne-scale deployment of $^{100}$Mo and $^{130}$Te isotopes.
Key design strategies include: (i) a novel detector architecture that reduces the exposed surface area of passive materials in the detector array by more than an order of magnitude; (ii) a tightly packed array of BGO scintillators operating as an active cryogenic veto system; and (iii) enhanced Neganov-Trofimov-Luke light detectors to suppress pile-up background for $^{100}$Mo and enable alpha-beta discrimination in $^{130}$TeO$_2$.
A dedicated cryogenic infrastructure has been installed and validated at the Modane Underground Laboratory (LSM), providing the necessary environment for low-background operations. Data-taking with prototype detectors is currently ongoing to validate the technological solutions and optimize the final design. A first physics run with MINI-BINGO is foreseen for 2026.
We present the technical design of these concepts, results from prototype technologies in proof-of-concept measurements, initial preliminary results from Modane, and Geant4-based projections of the expected impact of these improvements in a CUORE/CUPID-scale experiment.Speaker: Claudia Nones (IRFU/DPhP) -
71
New physics in Neutrinoless double beta decay
In this talk, I will discuss the impact of NME uncertainties on the upper limit of the effective neutrino mass in the light neutrino mechanism, where the contribution of the short range contact term is also considered. In this scenario. On the other hand, I will discuss the neutrino mass dependent NME and derive the limit on the parameter space of the minimal Type-I seesaw model from the current available experimental data as well as the future sensitivities from the next-generation experiments.
Speaker: 景宇 朱
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65
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Neutrino Physics and Astrophysics: parallel session 2B North Hall #2
North Hall #2
Convener: Yosuke Ashida (Tohoku University)-
72
LHC Neutrino Physics at the FASER Experiment
The Large Hadron Collider (LHC) is not only the most powerful particle accelerator ever built but also a unique source of an intense, high-energy beam of neutrinos spanning all flavors, predominantly collimated in the forward direction. After nearly 15 years of LHC operation, the first detection of collider-produced neutrinos was achieved by the dedicated FASER and SND@LHC experiments. This milestone marks the emergence of a new research frontier: collider neutrino physics. The TeV-energy neutrino beam produced in proton-proton collisions at the LHC enables the study of the highest-energy neutrinos in a controlled laboratory setting, providing novel opportunities to advance our understanding of neutrino interactions, explore strong interaction dynamics in previously uncharted kinematic regimes, and probe Beyond Standard Model (BSM) physics. Additionally, these measurements have significant implications for astroparticle physics, offering crucial input for addressing open questions about high-energy neutrino production in astrophysical environments. With initial results released in 2023 and 2025, ongoing and future neutrino experiments at the LHC will play a pivotal role in expanding our knowledge of QCD, neutrino properties, and new physics searches. This review presents the current status, first experimental results, and future prospects of collider neutrino studies at the LHC.
Speaker: Tomohiro Inada (Kyushu University) -
73
The FLArE Experiment at the Forward Physics Facility for High Energy Neutrino and Dark Matter Searches at LHC
The Forward Physics Facility (FPF) is a proposed program to build an underground cavern with the space and infrastructure to support a suite of far-forward experiments at the Large Hadron Collider in the High Luminosity era (HL-LHC). The Forward Liquid Argon Experiment (FLArE) is a Liquid Argon Time Projection Chamber (LArTPC) based detector designed for very high-energy neutrinos and search of dark matter in FPF, 620 m from the ATLAS interaction point in the far-forward direction. With a fiducial mass of 10 ton, FLArE will detect millions of neutrinos at the highest energies ever detected from a human source and will also search for Dark Matter particles with world-leading sensitivity in the MeV to GeV mass range. The LArTPC technology used in FLArE is well-studied for neutrino and dark matter experiments, however the use at the LHC requires specific targeted R&D. It offers excellent spatial resolution and particle identification. In this talk, I will overview the physics reach, the preliminary design, and the needed detector R&D
Speaker: Wenjie Wu (Institute of Modern Physics, Chinese Academy of Sciences) -
74
Neutrino Physics with the SND@LHC Experiment
The SND@LHC experiment was designed to perform measurements with neutrinos produced at the LHC within the unexplored pseudo-rapidity range of 7.2 < 𝜂 < 8.6. Located 480 m downstream of IP1 in the unused TI18 tunnel, this compact and stand-alone experiment employs a hybrid detector system consisting of 800 kg of tungsten plates interleaved with emulsion and electronic trackers, complemented by a calorimeter and a muon detection system. This configuration allows for the efficient identification of all three neutrino flavors, thereby opening new
opening a unique opportunity to probe the physics of heavy flavour production at the LHC, particularly in regions inaccessible to existing experiments such as ATLAS, CMS, and LHCb.
Exploring this region is also crucial for future circular colliders and predictions of very high-energy atmospheric neutrinos. Furthermore, the detector's design is adept at searching for Feebly Interacting Particles through distinctive scattering signatures. Since its initiation in 2022, the SND@LHC experiment has successfully operated during LHC Run 3 and collected 290 fb−1 of data. This presentation will summarize the results obtained thus far, the methodologies employed, and the implications for advancing our understanding of neutrino physics.Speaker: Onur Durhan (Atilim University) -
75
IceCat-2: An Updated Catalog of High-Energy Neutrino Alerts from IceCube
We present IceCat-2, the planned update of IceCube's public catalog of high-energy neutrino alerts, which builds on the first release, IceCat-1. The original catalog included all real-time alerts sent out since 2016, as well as earlier events from 2011 onward that would have triggered alerts if the system had been active at the time. IceCat-2 includes more recent alerts and reprocesses the entire dataset using a new reconstruction method implemented into the realtime stream in September 2024. This updated method significantly improves the precision and statistical coverage, with which we can determine the direction of incoming neutrinos, reducing the typical uncertainty in area by a factor of ~5 compared to previous analyses. With this improvement, we can more effectively search for connections between IceCube alerts and known astrophysical sources, such as gamma-ray and X-ray sources. The improved catalog enables new studies aimed at identifying counterparts to high-energy neutrino alerts, offering deeper insight into the nature and location of potential cosmic accelerators.
Speaker: Nora Valtonen-Mattila (Ruhr Universität Bochum) -
76
IceCube Search for MeV Neutrinos from Mergers using Gravitational Wave Catalogs
We report on a search using the IceCube Neutrino Observatory for MeV neutrinos from compact binary mergers detected through gravitational waves during the LIGO-Virgo-KAGRA (LVK) O1, O2, and O3 observing runs. The search focuses on events involving at least one neutron star, such as binary neutron star (BNS) and neutron star–black hole (NSBH) mergers, which may produce a burst of thermal neutrinos due to the hot and dense conditions created during the merger. We looked for short-time increases in IceCube’s detector activity around each gravitational-wave event, using four time windows centered on the merger time. We also performed a binomial test for two populations, those with and without at least one Neutron Star. No significant excess of neutrinos was found. We set upper limits on the MeV neutrino flux for each event, and we place constraints on MeV neutrino emission from mergers that have at least one Neutron Star. We showcase upper limits for GW170817, the first confirmed BNS merger, providing one of the strongest limits to date on MeV neutrino emission from such sources.
Speaker: Nora Valtonen-Mattila (Ruhr Universität Bochum) -
77
Investigating Neutrino Emission from Gamma-Ray (Galactic) Sources with KM3NeT/ARCA and ANTARES
High-energy neutrinos are unique messengers that offer insights into the mechanisms powering the most extreme cosmic accelerators. Astrophysical sources capable of producing cosmic rays are expected to emit both neutrinos and gamma rays, establishing a strong connection between these two signals. By modelling the link between observed gamma-ray spectra and the expected neutrino flux, it is possible to identify promising targets for neutrino detection.
In this work, we focus on gamma-ray sources identified by experiments such as LHAASO and HAWC, estimating their neutrino emissions and evaluating their detectability with the KM3NeT/ARCA and ANTARES neutrino telescopes. KM3NeT/ARCA, currently under construction in the Mediterranean Sea, will ultimately instrument about one cubic kilometer of seawater. Although still being deployed, the detector is already collecting data with a partial configuration. ANTARES, located off the coast of Toulon (France), was the first deep-sea neutrino telescope in the Mediterranean; it operated from 2007 to 2022 with an instrumented volume of about 0.01 km³.
The analysis combines the available ARCA dataset — corresponding to approximately 640 days of livetime — with the full dataset recorded by ANTARES over 15 years of operation. Both experiments are integrated within a common analysis framework, allowing for a joint search for neutrino emission from a selected catalogue of Galactic gamma-ray sources.
Sensitivity estimates for the completed ARCA detector are also provided based on detailed simulations. The combined dataset improves the coverage of the TeV–PeV energy range and enhances sensitivity across a wide portion of the sky.
These results support ongoing efforts to identify the sources of high-energy cosmic neutrinos and contribute to the broader field of multi-messenger astrophysics.Speaker: Vittorio Parisi (INFN Genova, University of Genova) -
78
Detection of a Muon Burst Coincident with KM3-230213A
The detection of a 220 PeV muon neutrino by the KM3NeT neutrino telescope presents a unique opportunity to investigate the Universe at extreme energies. Three scenarios have been proposed to explain this event: emission from a transient point source, diffuse astrophysical background emission, and line-of-sight interactions of ultrahigh-energy cosmic rays. At present, no other detectors have observed events coincident with KM3-230213A, supporting the diffuse emission scenarios over the transient one.
In this study, we analyze the counting rate recorded by the YangBaJing muon telescope on February 13, 2023, which shows an excess of 3000 ± 600 events over the atmospheric muon background. The distribution of the excess is consistent with an exponential profile starting at 01:17 UTC, with a decay time of approximately 400 seconds. The counting rate excess is observed exclusively in the telescope channel aligned with the direction of KM3-230213A (RA = 94.3°, Dec = −7.8°).
The estimated probability of a chance coincidence with the KM3-230213A event is approximately 10⁻³. If confirmed, this detection would favor the hypothesis of an astrophysical transient source and allow for preliminary inferences about the source’s properties.Speaker: Francesco Nozzoli (Trento University & INFN-TIFPA)
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72
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Underground Laboratories: parallel session 2 North Hall #3
North Hall #3
Convener: Pia Loaiza (IJCLab, IN2P3/CNRS Université Paris-Saclay)-
79
In-situ environmental radiation background measurement in the second phase of CJPL
China Jinping Underground Laboratory (CJPL), with a rock overburden of about 2400 m, provides low radiation background environment necessary to frontier scientific researches, such as dark matter direct detection and neutrinoless double beta decay experiments. Due to almost filled space of the first phase of CJPL and the requirement of future physical experiments, construction of the second phase of CJPL (CJPL-II) funded by National Major Science and Technology Infrastructure Construction Projects of China was started in December 2020. The civil engineering of CJPL-II was completed at the end of 2023. In this work, we report the measured results of major environmental radiation, including cosmic-ray muons, gamma-rays and radon, in CJPL-II.
Speaker: Peng Zhang (Tsinghua University) -
80
Measurement of the Cosmic Muon Flux at the Stawell Underground Physics Laboratory using the muon veto of the SABRE South Experiment
The SABRE South experiment, currently being commissioned at the Stawell Underground Physics Laboratory (SUPL), will use high-purity NaI(Tl) crystals to investigate the seasonal modulation of dark matter. The cosmic muon flux, also expected to exhibit seasonal dependence, must be tagged and rejected to isolate the small signal. Eight EJ200 plastic scintillator panels, equipped with Hamamatsu R13089 PMT pairs at the ends, will be arranged in a planar configuration on top of SABRE South, covering an area of 9.6 m2. They will provide a muon veto system with fast timing characteristics.
This talk presents the measurement of the time-integrated muon flux at SUPL, relying on the SABRE South muon veto system and its data acquisition and processing pipeline. This study was conducted with approximately one year of data collected between 2024 and 2025, utilising the muon veto system arranged in a telescopic configuration. SUPL, located 1,025 metres below ground in Victoria, Australia, has a flat overburden, roughly 2.8 km of water equivalent, which will significantly reduce the muon background. The mine location facilitates a thorough understanding of the overburden, allowing tight constraints on systematic uncertainties through a muon flux simulation framework, which is also discussed in the talk.
Speaker: Mr Guangyong Fu (University of Melbourne) -
81
Cosmogenic Radiation Characterization for the Colorado Underground Research Institute
Underground facilities are often sought after due to their rock overburden, which provides natural protection from ionizing cosmogenic radiation, such as the near-elimination of cosmogenic muons. However, for many efforts such as dark matter searches or neutrinoless double beta decay experiments, the surviving cosmogenic muon and muon-induced events still present a significant background. One way to characterize and address these backgrounds, especially for R&D and equipment benchmarking, is to move to shallow underground facilities such as the new Colorado Underground Research Institute (CURIE). In this talk, we present the characterization of cosmogenic muon and secondary backgrounds for CURIE located in the Edgar Experimental Mine in Idaho Springs, CO. The underground muon flux was simulated using the MUTE software package and subsequently validated with direct measurements, yielding agreement within 10%. The overburden at CURIE provides a factor of 700 reduction relative to the sea level surface muon flux. Additionally, a new depth-intensity relationship was developed to interpret the overburden, resulting in an equivalent shielding of 415 meter-water-equivalent (m.w.e.) relative to a flat overburden. Lastly, we discuss the muon-induced secondaries which were simulated by coupling the underground muon angular and energy spectrum from MUTE with Geant4.
Speaker: Dakota Keblbeck (Colorado School of Mines) -
82
An LNGS Mobile Neutron Detector (ALMOND): Mapping Ambient Neutron Background of Gran Sasso National Laboratory
In deep underground laboratories, environmental neutrons, which are produced at the cavern walls, introduce a source of background to rare event searches, such as dark matter direct detection and neutrinoless double beta decay experiments as well as low-cross section measurements for nuclear astrophysics. The flux and spectrum of the ambient neutrons vary greatly with time and location. Precise knowledge of this background is necessary to devise shielding and veto mechanisms, improving the sensitivity of the neutron-susceptible underground experiments.
ALMOND, currently in operation, is a low-flux neutron spectrometer developed for the LNGS underground laboratory to measure the ambient neutron background of the entire facility. In this talk, an overview of the design, construction and calibration of ALMOND will be presented. Furthermore, the results of the first underground measurements will be shown along with an outlook for future measurements. The project was supported by the German Federal Ministry of Education and Research (BMBF) under the grant number 05A21VK1.
Speaker: Melih Solmaz (Heidelberg University) -
83
The HENSA project for the characterization of neutron fluxes in underground laboratories
HENSA is a high efficiency neutron spectrometer based on the same principle than Bonner sphere systems. The detector has been used for years in the Canfranc Underground Laboratory (LSC) in order to assess the neutron flux underground. In particular, for more than 3 years HENSA has been being used in hall B of the LSC with obejective to characterize the neutron flux that could affect the ANAIS-112 dark-matter experiment.
In this work, the last results from the HENSA campaign at LSC will be discussed, including the temporal evolution and energy spectra. In addition, the status of the recently started HENSA collaboration at the Gran Sasso National Laboratory (LNGS) will be shown.
Speaker: Nil Mont (Universitat Politècnica de Catalunya) -
84
Radon-222 Screening Capability at SNOLAB
Radon-222 is a limiting background in many leading dark matter and low-energy neutrino experiments. At SNOLAB, we have various radon instruments dedicated to material screening and to the measurement of radon concentration in N₂ gas systems and in ultra-pure water. My talk will focus on describing these instruments. In addition, it will describe a recent development aimed at improving our N₂ gas assay capability.
Speaker: Nasim Fatemighomi (SNOLAB) -
85
Element synthesis in star by deep underground nuclear astrophysics JUNA experiments
The Jinping Underground experiment for Nuclear Astrophysics (JUNA) is located in the ultra-low background of the China Jingping Underground Laboratory (CJPL). JUNA is aiming to conduct experiments for directly studying crucial reactions at stellar energies in the evolution of stars. In 2020, JUNA commissioned an mA level high current accelerator based on an ECR source, as well as high efficiency BGO and 3He detectors. These combination enabled JUNA to perform direct measurements of key nuclear reactions in 10-13 b sensitivity with the beam exposure of few hundreds of Coulomb, including Run 1 experiments of 25Mg(p,γ)26Al, 19F(p,αγ)16O, 19F(p,γ)20Ne, 13C(α,n)16O, 12C(α,γ)16O, and 18O(α,γ)20Ne with improved precision and closer to the Gamow window. These precise reaction rates provide valuable insights into the high precision astrophysics simulation. The highlight, upgrades and Run 2 plans of JUNA experiments will be presented. The progress of other underground nuclear astrophysics experiments such as LUNA, CASPAR and Felsenkeller, will be reviewed.
Speaker: Xiaodong Tang (Institute of Modern Physics, CAS)
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79
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Social Events: Conference Dinner A-Si-Niu-Niu Restaurant
A-Si-Niu-Niu Restaurant
Torch Square
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On-site registration (start at Saturday 23/08) International Conference Center
International Conference Center
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Plenary session Lufeng Hall
Lufeng Hall
Convener: Kaixuan Ni-
86
WIMPs and dark sector models
Are WIMP (weakly interacting massive particles) dark matter models still viable? A years-long, concerted global search for such particles has so far failed to find conclusive evidence for their existence. Despite this, there are still regions of parameter space that still allow for WIMPS to be the dark matter of the Universe. At the same time, the lack of non-gravitational evidence for WIMPs has also motivated building simple models where the dark matter resides in a ``dark sector’’ with parametrically small couplings to standard model states. Such models can offer flexibility and novel experimental targets. This talk will review WIMP and dark sector models with a particular focus on experimental prospects.
Speaker: David McKeen -
87
Noble liquid observatories for dark matter and astrophysical neutrinos
Over the past two decades, noble liquid detectors located deep underground have made remarkable advancements, significantly enhancing their ability to explore a diverse parameter space for dark matter particles. These increasingly sensitive detectors are now evolving into versatile particle astrophysics observatories. Notably, xenon-based detectors are beginning to see solar neutrino-nucleus elastic scattering, a phenomenon often referred to as the “neutrino fog.” In this talk, I will provide an overview of recent developments in noble liquid observatories, and highlight their potentials to address fundamental questions in particle physics in the decades to come.
Speaker: Ning Zhou (Shanghai Jiao Tong University) -
88
From Electrons to Phonons: Experimental Frontiers of Low-mass Dark Matter Searches
The nature of dark matter remains one of the mysteries in modern physics. While traditional searches have focused on the weak-scale mass range, a growing body of theoretical and experimental work is now exploring the possibility of low-mass dark matter, with mass spanning from MeV down to sub-eV scales. This shift in focus has sparked a wave of technological innovation aimed at detecting feeble interactions between light dark matter and ordinary matter. In this review, I will present the current landscape of experimental technologies designed to probe light dark matter across various detection channels, with focus on electron-recoil detectors using semiconductors and superconductors and cryogenic calorimeters with eV-scale thresholds. The principles behind these technologies and the challenges they face in terms of background mitigation and scalability will be discussed.
Speaker: Suerfu Burkhant (High Energy Accelerator Research Organization (KEK))
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86
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Coffee break International Conference Center
International Conference Center
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Plenary session Lufeng Hall
Lufeng Hall
Convener: Yuanning Gao-
89
Axion dark matter (theory & experiment)
We review the theory and experimental status of the axion as a solution to the strong-CP problem and a leading ultra-light, wave-like dark-matter candidate. We summarize the Peccei–Quinn mechanism, axion couplings, and cosmological production via misalignment. Astrophysical probes（stellar cooling, pulsar-timing arrays, and black-hole superradiance，etc）already set strong bounds across wide parameter ranges, informed by radio and millimeter-wave observations. In parallel, laboratory searches employ resonant cavities (including superconducting implementations), LC and broadband circuits, precision polarimetry and light-shining-through-walls experiments, and NMR-based and fifth-force techniques. These complementary approaches cover distinct mass–coupling windows yet leave substantial discovery space. Looking ahead, advances in quantum detection and coordinated sensor networks promise order-of-magnitude sensitivity gains and an expanded reach to higher masses and weaker couplings.
Speaker: 菁 舒 -
90
Dark matter searches at colliders
The nature of dark matter, one of the most compelling open questions in fundamental physics, is still unknown. A comprehensive search program has developed over the past decades, spanning direct detection experiments, indirect detection via astrophysical signals, and collider-based production. In this talk, we focus on collider searches for dark matter, particularly at the Large Hadron Collider, and discuss how these efforts complement other detection approaches. We will touch upon the theoretical frameworks commonly used to interpret collider results, and highlight recent results and constraints, where initial emphasis on mono-X searches and invisible Higgs decays have over the past years been extended to include long-lived particle searches, light mediators or non-minimal dark sectors. We will conclude with future prospects for collider-based dark matter detection, and how these integrate into a global, multi-pronged strategy to uncover the particle nature of dark matter.
Speaker: Steven Lowette (Vrije Universiteit Brussel) -
91
Probing dark matter self-interactions in the sky
Although the existence of dark matter is well established, its nature remains elusive. Dark matter could be part of the "dark sectors," comprising hidden particles with new interactions. Such interactions could cause dark matter to self-interact, altering the formation and evolution of dark matter halos. Self-interacting dark matter halo undergoes gravothermal evolution, where the central halo first forms a core that ultimately collapses. The resulting cored and collapsed phases diversify the density profiles of dark matter halos. In particular, the ultra-dense substructures produced in the collapsed phase can be effectively probed by gravitational lensing. Furthermore, collapsed halos may seed the high-redshift supermassive black holes, addressing a longstanding puzzle in astrophysics.
Speaker: Yiming Zhong
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89
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Lunch Yu’ou Building
Yu’ou Building
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Dark Matter and Its Detection: parallel session 3A Conference Room F2-R1
Conference Room F2-R1
Convener: Ziqing Hong (University of Toronto)-
92
The SuperCDMS SNOLAB experiment
The Super Cryogenic Dark Matter Search (SuperCDMS) SNOLAB experiment is currently under construction 2 km underground at the SNOLAB facility near Sudbury, Canada. The experiment will utilize 24 cryogenic germanium and silicon calorimeter detectors, with the aim of achieving world-leading sensitivity in the direct search for dark matter (DM) particles interacting with nuclei, spanning DM particle masses from 0.5 to 5 GeV. Additionally, the experiment will investigate electron scattering of MeV-scale DM particles and the absorption of eV-scale dark photons and axion-like particles (ALPs). This talk will describe the detector technology, highlighting the achievements in the experiment installation and outline the expected scientific impact.
Speaker: Dr Emanuele Michielin (Karlsruhe Institute of Technology) -
93
Towards the deployment of DAMIC-M: status and latest results
The DAMIC-M (DArk Matter In CCDs at Modane) experiment is scheduled to begin operations at the Modane underground laboratory (LSM) in early 2026. This talk presents the current status of the project, highlighting recent results from its prototype—the Low-Background Chamber (LBC)—and progress on detector construction at LSM. Data from the LBC have been used to exclude theoretical benchmarks where hidden-sector particles make up the dominant component of dark matter via freeze-in or freeze-out mechanisms. In preparation for DAMIC-M, 28 low-background CCD modules packaged at the University of Washington will undergo underground testing at LSM for detailed characterization prior to their integration into the full detector array.
Speaker: Michelangelo Traina (Instituto de Física de Cantabria) -
94
Search for light dark matter with CRESST-III
The CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) experiment, located in Laboratori Nazionali del Gran Sasso - INFN in Italy, aims to directly detect light dark matter (DM) particles. Scintillating CaWO$_4$ crystals, equipped with Transition Edge Sensor (TES), are operated as cryogenic detectors at mK temperatures, as target material for DM-nucleus scattering. CRESST achieved outstandingly low nuclear recoil thresholds $\mathcal{O}$(10-30 eV), yielding world-leading sensitivity for light dark matter particles for mass below 1.7 GeV/$c^2$. In 2019, CRESST observed for the first time an excess of events rising exponentially below 200 eV, known as the Low Energy Excess (LEE), that is currently limiting the sensitivity of many experiments in the field and whose origin remains unclear. To better scrutinise LEE and produce improved DM results, CRESST developed the DoubleTES approach that, using the coincidence readout of two TESs on the same detector, allows suppression of events generated near the sensor. The most recent updates on the identification and rejection of LEE are reported, together with the most recent results on DM.
Speaker: Carlo Bucci (INFN - LNGS) -
95
Scientific Prospects and Technical Innovations in the CDEX-50 Experiment
The CDEX program has been pursuing the direct detection of light dark matter candidates using an array of germanium detectors at the China Jinping underground laboratory, deepest operating underground facility in Sichuan, China. Recent investigations have explored the modulation effects of light WIMPs, WIMP-nucleus interactions via the Migdal effect, dark photon models, solar axions, axion-like particles, and new mechanics dark matter candidates. An upgraded CDEX-50 dark matter experiment is proposed and in progress, accompanied by R&D initiatives on crucial low radioactivity technologies, including electroformed copper at the underground site, the fabrication of ultra-low-background front-ends for various germanium detector types, and the operation of a germanium detector with its bare crystal immersed in liquid nitrogen with radon mitigation. Additionally, potential hybrid Anti-Compton detectors and a ~1700 cubic meter liquid nitrogen tank are being explored. The results and future prospects of the CDEX dark matter program will be presented.
Speaker: Shin Ted Lin -
96
The Direct Search Experiment for Light Dark Matter (DELight): Overview and Perspectives
Driven by the null results in the searches for dark matter, the field of direct dark matter detection is constantly evolving to push new frontiers. Ultimately, a vast parameter space for dark matter masses below a few GeV is yet to be explored. That said, low mass dark matter candidates necessitate novel detector designs with lower thresholds and alternative target materials compared to e.g., the xenon-based experiments currently providing the strongest overall constraints on many dark matter models.
The Direct search Experiment for Light dark matter (DELight) will deploy a target of superfluid $^4$He instrumented with large area microcalorimeters (LAMCALs) based on magnetic microcalorimeter (MMC) technology in a setup optimized for low mass dark matter searches. The talk will present an overview of this novel upcoming experiment, including preliminary background models and sensitivity projections.
Speaker: Melih Solmaz (Heidelberg University)
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92
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Dark Matter and Its Detection: parallel session 3B Conference Room F2-R2
Conference Room F2-R2
Convener: Yongcheng Wu (Nanjing Normal University)-
97
SUSY Dark Matter at the LHC?!
For the first time the two big LHC experiments, ATLAS and CMS, report consistently about excesses in the search for EW SUSY particles, seen in two different search channels by each experiment. We interpret these excesses as the production of two light MSSM particles, decaying to Dark Matter (as naturally predicted by the MSSM). These interpretations make clear predictions for future collider experiments, but also for the next round of (Xenon- and Argon-based) Direct Detection experiments.
Speaker: Sven Heinemeyer (IFT (CSIC, Madrid)) -
98
A Unified Framework for Dwarf Galaxy Cores and Cluster Substructure Cusps via Self-Interacting Dark Matter with Mass Segregation
Self-interacting dark matter (SIDM) provides a promising solution to small-scale structure anomalies, yet a unified explanation across mass scales remains challenging. Recent dwarf galaxy surveys favor a relatively small cross section of $\sim 0.3 \rm cm^2/g$---insufficient to induce core collapse---while strong lensing signals in galaxy clusters require dense inner subhalos typically associated with much larger cross sections. We demonstrate that this tension can be resolved in two-component SIDM models, where even modest inter-component interactions lead to efficient mass segregation in massive halos. This enhancement occurs without requiring large self-interaction rates, as the strength of SIDM effects scales with the scale density $\rho_s$ and radius $r_s$ as $\sigma_{\rm eff}/m r_s \rho_s^{3/2}$. Consequently, the impact is amplified in cluster subhalos, where both $\rho_s$ and $r_s$ are large, while remaining insignificant in dwarf galaxies. Using a set of cosmological zoom-in simulations of clusters and high-resolution controlled simulations of dwarf halos, we show that this framework can simultaneously reproduce cored dwarfs and cuspy cluster substructures. Our results highlight two-component SIDM with mass segregation as a unified and testable framework for explaining structural features of dark matter halos that are otherwise puzzling.
Speaker: Daneng Yang (Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210023, China) -
99
Lensing signatures of self-interacting dark matter halos: an analytic approach
We present an analytic model for gravitational lensing by self-interacting dark matter (SIDM) halos that captures the full range of gravothermal evolution, including the core-collapse regime. Leveraging the universal behavior of SIDM halos, we calibrate the lensing potential using fluid simulations and derive closed-form expressions for the deflection angle and surface density profile. Our model improves upon existing parametric approaches by enabling accurate treatment of the steep inner density profiles that emerge during the late stages of evolution. We apply this framework to study characteristic lensing features such as critical curves and caustics, both for isolated halos and for subhalos embedded within a host. In particular, we examine how the evolution of core-collapsed subhalos modifies lensing observables. We release our method as a public tool on GitHub (https://github.com/HouSiyuan2001/SIDM_Lensing_Model), which is applicable to halos of any mass that can be described by our parametric density profiles. The tool is especially useful for modeling low-mass subhalos, whose collapse can lead to distinctive strong lensing signatures in SIDM scenarios.
Speaker: Siyuan Hou (Purple Mountain Observatory) -
100
3-Dimensional WIMP Effective Velocity Distribution
In the last (more than) three decades, more than 40 experiments have been built or are being planned to search for different WIMP candidates by direct detection of their (elastic) scattering signals off target nuclei in low-background underground laboratory detectors. For an estimate of the scattering event rate as well as for expected determinations of WIMP properties in the future, the velocity distribution of the WIMPs impinging on the detectors plays a crucial roll. In this talk, I will introduce a 3-dimensional WIMP "effective" velocity distribution, which, instead of the theoretically predicted velocity distribution of the "entire" Galactic Dark Matter particles, describes the "actual" velocity distribution of WIMPs "scattering off" (specified) target nuclei in an underground detector. Theoretical arguments will be discussed in detail first. Then numerical results based on our double Monte Carlo scattering-by-scattering simulation of 3-Dimensional elastic WIMP-nucleus scattering events will also be demonstrated. If there is enough time, I will also discuss and demonstrate an interesting (asymmetric) "forward-backward asymmetry" of the 3-D WIMP Galactic effective velocity distribution in both theoretical and numerical points of view.
Speaker: Chung-Lin SHAN (SCTIR) -
101
Charged lepton flavor violating light Dark Matter and muonium invisible decay
We explore lepton flavor violating (LFV) dark matter (DM) interactions within an effective field theory framework, considering the operators of the form $\bar \ell_j \Gamma \ell_i,{\tt DM}^2$ for $(ij) = (\mu e,, \tau e,, \tau \mu)$ and where DM can be scalar, fermion, and vector. We analyze the three-body decay $\ell_i \to \ell_j + {\tt DM} + {\tt DM}$, showing its utility in probing operator structure and DM mass. Using current bounds on LFV decays with invisible final states, we set strong constraints on the effective scale. For the $\mu e$ case, we also study the radiative decay $\mu \to e + {\tt DM} + {\tt DM} + \gamma$, and examine muonium invisible decays, which can be significantly enhanced. A future observation of para-muonium invisible decay would provide a clear signal of such LFV DM interactions.
Speaker: Sahabub Jahedi (South China Normal University)
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97
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Gravitational Waves: parallel session 3 Conference Room F1-R3
Conference Room F1-R3
Convener: KeJia Lee (Peking univerisity)-
102
Constraints on Lorentz and parity violations with gravitational waves
Gravitational wave (GW) observations offer a powerful tool for testing the fundamental Lorentz and parity symmetries of gravity. Any violation of these symmetries could manifest as deviations in GW propagation. In this talk, I will explore how current and future GW detections can constrain Lorentz- and parity-violating effects in gravity. I will introduce a systematic parameterization framework to describe potential deviations in GW propagation from general relativity in a cosmological background. Using this framework, we can construct modified GW waveforms, incorporating the effects of Lorentz and parity violations as predicted by various alternative gravity theories. Finally, I will present the latest results from our analysis of these modified waveforms using current GW data and discuss the prospects for placing even stronger constraints from future GW detections.
Speaker: Tao Zhu (Zhejiang University of Technology) -
103
Wave Effects of Gravitational Waves
Wave effects are a crucial aspect of gravitational waves. When the wavelength of GWs is comparable to or greater than the Schwarzschild radius of an object, the propagation of gravitational waves no longer follows geometrical optics, and coherence and interference can occur. Despite their significance, studying these wave effects can be challenging due to their complexity.
In this talk, I will discuss numerical techniques for simulating these effects in the gravitational field of a Schwarzschild black hole. I will talk about the back-scattering effect of the interaction between GWs and the background curvature. Finally, I will discuss the potential detectability of these wave effects in aLIGO.Speaker: Jian-hua He (Nanjing University) -
104
Gravitational Wave Birefringence in Fuzzy Dark Matter and Symmetron Cosmology
Gravitational wave (GW) birefringence is a remarkable phenomenon which provides a window to test partiy violation in gravity. In this talk, I would discuss our recent studies on the GW birefringence in the FDM and symmetron models. In particular, inspired by the complicated distributions of the Fuzzy dark matter (FDM) and the symmetron field in our Galaxy, we are led to considering the GW propagation over the light scalar profile of general spacetime dependence. We apply the well-known eikonal approximation to solve this technical problem. In the FDM case, it is shown that GWs exhibit the amplitude birefringence with the dominant contribution only depending on the GW frequency. More importantly, the birefringence factor shows a periodic time modulation with its period reflecting the FDM mass, which is the smoking gun to test this FDM-induced mechanism. In the symmetron model, we introduce a new $Z_2$-symmetric Chern-Simons-like coupling, which can also generate the amplitude birefringence. However, unlike the FDM case, the birefringence induced by the galactic symmetron field is suppressed due to its screening mechanism. Thus, the GW birefringence is dominantly generated by the extra-galactic symmetron distribution, which can be further used to place a reasonable constraint on this parity-violating coupling in the symmetron model.
Speaker: Da Huang -
105
A treatment to gravitational perturbations and Lorentz-violating effects with Lagrangian analysis
Since the first direct detection to the gravitational wave (GW), i.e., the event GW150914, it has emerged as a blockbuster during the past decade within the realm of theoretical physics. Specially, it provides us with an unprecedented opportunity in testing theories of gravity that beyond the scope of general relativity (GR), especially in the strong-field regime. One common way for extracting physical information and observables encoded in a theory’s Lagrangian is to execute the gravitational perturbations on it. Unfortunately, due to the sophisticated structure of, e.g., the Lorentz-violating (LV) theory, which predicts multiple horizons that beyond GR and plays an important role in constructing the quantum gravity, many attempts in this area are meeting a great challenge under the traditional treatment. To eliminate this challenge, here we will introduce a novel treatment for this sort of problems, which can be expediently referred as Lagrangian analysis. It can not only reveal the inherent stability of the theory but also lead us to the effective derivation process of the corresponding GWs. Hopefully, several research sub-branches, including the study of modified theories of gravity and their combinations with GW observations, will benefit from the development of this novel treatment to gravitational perturbations. More details will be given in the talk.
Speaker: Chao Zhang
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102
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High-Energy Astrophysics and Cosmic Rays: parallel session 3 Conference Room F1-R2
Conference Room F1-R2
Convener: Weiwei Xu (Shandong University)-
106
Highlights from the 10 years observations with CALET on the International Space Station
The CALorimetric Electron Telescope (CALET) space experiment is a high-energy astroparticle physics mission in operation on the International Space Station (ISS) since 2015 with excellent and continuous performance. The instrument consists of two layers of segmented plastic scintillators for the identification of cosmic-rays via a measurement of their charge (CHD), a 3 radiation length thick tungsten-scintillating fiber imaging calorimeter (IMC) and a 27 radiation length thick lead-tungstate calorimeter (TASC). The primary goals of the CALET mission include studying the details of galactic cosmic-ray acceleration and propagation, and searching for possible nearby sources of high-energy electrons and dark matter signatures. The CALET experiment is designed to measure the flux of cosmic-ray electrons (including positrons) up to 20 TeV (and gamma-rays up to 10 TeV), and also proton, helium and heavy nuclei up to the PeV region. CALET also measures the relative abundances of ultra-heavy galactic cosmic rays (UHGRC) above atomic number Z=28 (nickel) and past Z=44 (ruthenium).
Here, we present the highlights of the CALET latest science results stemming from almost 10 years of observations for various components of cosmic rays (leptons, hadrons, and photons). Some results on the observations of solar modulation during nearly one solar cycle will also be included, together with the study of space-weather phenomena, X-ray and soft gamma-ray transients, and searches of electromagnetic counterparts of LIGO/Virgo gravitational wave events. Characterization of on-orbit performance, with approximately 20 million events above 10 GeV recorded per month, will be reported.Speaker: Kazuyoshi Kobayashi -
107
Latest results from the DAMPE space mission in more than 9 years
The space-based DAMPE (DArk Matter Particle Explorer) detector has been taking data since its successful launch in December 2015. Its main scientific goals include the indirect search for dark matter signatures in the cosmic electron and gamma-ray spectra, the measurements of galactic cosmic ray fluxes from tens of GeV up to sub-PeV and high energy gamma ray astronomy above a few GeV, it is also a sensitive monitor for the space weather related with the solar acitivity. Latest results on all the mission science goals will be given, with particular focus on spectral measurements up to the sub-PeV region.
Speaker: Pengxiong Ma (PMO) -
108
Cosmic-Ray Nuclei Flux Measurements with the DAMPE Experiment
The DArk Matter Particle Explorer (DAMPE), which is a space-based high energy particle detector, has been operated in orbit for nearly ten years. Thanks to its large geometric factor, good charge resolution and wide dynamic range in energy measurement, DAMPE can provide valuable insights on the energy spectra of cosmic-ray up to hundreds of TeV. These measurements are fundamental to achieve a better understanding of cosmic ray origin, mechanism of acceleration and propagation in the Galaxy. In this contribution, we present a detailed analysis and the latest results from the DAMPE experiment on the flux measurements of primary cosmic-ray nuclei, including carbon, oxygen, and iron, as well as secondary cosmic-ray nuclei such as lithium, beryllium, and boron.
Speaker: Yifeng Wei (University of Science and Technology of China) -
109
Properties of Cosmic Beryllium Isotopes: Results from the Alpha Magnetic Spectrometer
Beryllium nuclei in cosmic rays are expected to be secondaries produced by the fragmentation of primary cosmic rays during their propagation in the Galaxy. Therefore, their fluxes contain essential information on cosmic ray propagation and sources. Secondary-to-primary flux ratios provide measurements of the material traversed by cosmic rays in their journey through the Galaxy. The 10Be/9Be ratio measures the cosmic ray propagation volume in the Galaxy. Current measurements of the 10Be/9Be ratios are limited to energies below 2 GeV/n (~5.5 GV) , and are affected by large uncertainties. Individual fluxes of 7Be, 9Be and 10Be, have only been measured below 0.4 GeV/n. (~1.9 GV). In this contribution, we present the measurement of the 7Be, 9Be, 10Be fluxes and their ratios, in the uncharted energy region ranging from 1.9 GV Gv to 40 GV based on data collected by AMS during its first 13.5 years of operation on the International Space Station.
Speaker: Yao Chen (山东高等技术研究院) -
110
Properties of Cosmic Li Isotopes Flux
We present the first measurement of cosmic-ray fluxes of 6Li and 7Li isotopes in the rigidity range from 1.9 to 25 GV. The measurements are based on 0.97 million 6Li and 1.04 million 7Li nuclei collected by the Alpha Magnetic Spectrometer (AMS) on the International Space Station from May 2011 to October 2023. We observe that over the entire rigidity range the 6Li and 7Li fluxes exhibit nearly identical time variations. Above ~7GV, we find an identical rigidity dependence of the 6Li and 7Li fluxes. This shows that they are both produced by collisions of heavier cosmic-ray nuclei with the interstellar medium and, in particular, excludes the existence of a sizable primary component in the 7Li flux.
Speaker: Hai Chen (Zhejiang University) -
111
Unique Properties of Secondary Cosmic Rays: Results from the Alpha Magneti Spectrometer
We present high statistics measurements of the secondary cosmic rays Lithium, Beryllium, Boron, Fluorine, and Phosphorus based on 13.5 years of AMS data. The properties of the secondary cosmic ray fluxes and their ratios to the primary cosmic rays Li/C, Be/C, B/C, Li/O, Be/O, B/O, and F/Si and P/Si are discussed. The systematic comparison with the latest GALPROP cosmic ray model is presented.
Speaker: Dr Zhaomin Wang (Shandong Institue of Advanced Technology (SDIAT)))
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106
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Neutrino Physics and Astrophysics: parallel session 3A North Hall #1
North Hall #1
Convener: Manfred Lindner (Max Planck Institute for Nuclear Physics)-
112
A study of neutrinoless double electron capture of $^{40}\mathrm{Ca}$ with the AMoRE-I experiment
The AMoRE collaboration aims to investigate rare processes, including neutrinoless double electron capture ($0\nu2\mathrm{EC}$), an intriguing alternative to neutrinoless double-beta decay for exploring the fundamental nature of neutrinos. We will present a comprehensive analysis of the $0\nu2\mathrm{EC}$ process in $^{40}\mathrm{Ca}$, utilizing the high-purity, enriched calcium molybdate ($^{48dep}\mathrm{Ca}^{100}\mathrm{MoO}_4$) detectors from the AMoRE-I experiment.
Taking advantage of the low-background environment and high energy resolution of the AMoRE-I setup, we thoroughly searched for the $0\nu2\mathrm{EC}$ signature at the decay’s Q-value (193.5 keV). In this presentation, we report preliminary studies on the half-life of $0\nu2\mathrm{EC}$ in $^{40}\mathrm{Ca}$ and highlight the sensitivity of low-temperature calorimeters in probing rare decay processes.
Speaker: Bijaya Sharma (IBS School, UST) -
113
Benchmarking 0𝛎ββ-decay nuclear matrix elements with the MONUMENT Experiment
The nuclear matrix elements of neutrinoless double beta decay are a dominant source of uncertainty when connecting the decay rate to article-physics properties. Due to its large momentum transfer, ordinary muon capture offers a promising method to benchmark nuclear matrix element calculations under similar conditions. When a muon is captured on a double beta daughter isotope, the resulting nucleus reflects the virtual intermediate state of the double beta transition. Studying its de-excitation yields insight into the nuclear structure relevant for neutrinoless double beta decay. Within the MONUMENT experiment, ordinary muon capture was measured on various isotopes including $^{76}$Se, $^{136}$Ba, and $^{48}$Ti. The measurements were performed at the Paul Scherrer Institute. The measurements will be presented along with a description of the setup and initial findings from the analysis.
Speaker: Elizabeth Mondragón (Max Planck Institute for Nuclear Physics / Technical University of Munich) -
114
Detector response study of cryogenic scintillating Li$_2$MoO$_4$ detectors for next generation $0\nu\beta\beta$ search
Next generation $^{100}$Mo based neutrinoless double beta decay searches like AMoRE and CUPID require a precise understanding of the detector response of cryogenic $^{100}$Mo based detectors at the Q-value (3034 keV) of the $0\nu\beta\beta$ decay. However, common long-lived calibration sources like $^{208}$Tl provide the last intense calibration peaks at or below 2.6 MeV and hence require an extrapolation to the region of interest (ROI). In the CUPID-Mo demonstrator we operated 20 enriched Li$_2$MoO$_4$ detector modules at ~20 mK for an extended period of more than 1 year proving the competitiveness of this detector tenchnology for future $0\nu\beta\beta$ searches. We also performed a dedicated ~3 week calibration campaign with a specially irradiated $^{56}$Co source to directly assess the detector response with high energy $\gamma$ lines at and above the $^{100}$Mo Q-Value. In this contribution we will present results of this calibration campaign with respect to a typical detector response extrapolation in terms of energy bias and energy resolution broadening at the Q-value of $^{100}$Mo. In addition, the rich $\gamma$ spectrum of the $^{56}$Co source allowed for an assessment of the detector response for different event topologies in particular of well localised electron-positron pair creation events with escape of the two 511 keV $\gamma$'s versus multi-site events like typical Compton + Photoabsorption events for full energy peaks in the few MeV range. We observe a small but statistically significant shift of ~0.6 keV in the energy reconstruction of these event types, which if confirmed should be considered as systematic for the $0\nu\beta\beta$ ROI.
Speaker: Benjamin Schmidt (CEA IRFU/DPHP) -
115
High-precision study of 2νββ of $^{130}$Te from the CUORE experiment
The two-neutrino double-beta decay (2νββ) of $^{130}$Te offers a unique window into its underlying nuclear structure and provides essential benchmarks for neutrinoless double-beta decay (0νββ) searches. We present the most precise measurement to date of the 2νββ half-life of $^{130}$Te from the CUORE experiment. The half-life, based on 1038 kg·yr TeO$_2$ exposure, is determined to be T$^{1/2}_{2ν} = (9.32 ^{+0.05 }_{-0.04} (stat.) ^{+0.07}_{-0.07} (syst.)) \cdot 10^{20}$ yr, marking a two-fold improvement in precision compared to previous measurements. Beyond refining the half-life measurement, this result leverages a 70% enhancement in signal-to-background ratio thereby enabling the first application of a spectral shape analysis using next-to-leading-order 2νββ formalism in $^{130}$Te. This analysis extracts ratios of higher-order nuclear matrix elements—parameters that are notoriously challenging to probe experimentally. These results significantly advance double-beta decay physics, offering stringent constraints on nuclear models and enhancing the interpretive power of future 0νββ searches.
Speaker: Stefano Dell'Oro (University of Milano-Bicocca) -
116
Improving the sensitivity to effective Majorana mass with combined analysis of multiple 0νββ transitions in large xenon detectors
Large xenon time projection chambers (TPCs) have become important tools in underground physics. Next-generation PandaX-xT and XLZD TPCs will contain 4-7 tons of Xe-136 in their active volumes. We propose a combined analysis of neutrinoless double beta decay (0νββ) to the ground state and excited states (0νββ-ES) of the daughter nucleus to enhance the search sensitivity. The improved signal identification and background suppression achieved through the characteristic beta+gamma coincidence signature of 0νββ-ES allows us to utilize a larger fiducial volume while maintaining low background rates. Stronger constraints on the effective neutrino mass can be obtained by this approach, despite the fact that the half-life for decays to excited states is typically one to three orders of magnitude longer than that for decays to the ground state. These results demonstrate the importance of simultaneously probing multiple decay channels in future 0νββ experiments, while highlighting the unique advantages offered by large xenon TPCs.
Speaker: Ke Han (Shanghai Jiao Tong University)
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112
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Neutrino Physics and Astrophysics: parallel session 3B North Hall #2
North Hall #2
Convener: Prof. Yufeng Li (Institute of High Energy Physics, Beijing)-
117
Solar neutrino results with the full data period until Super-Kamiokande-IV
As the world's largrest water Cherenkov detector, Super-Kamiokande (SK) has confirmed the MSW effect through observation of solar neutrino.A newly developed spallation removal method for SK-IV has improved the signal efficiency by 12.6%.The measurements from SK-I to SK-IV has verified the day-nignt asymmetry and large mixing angle results. The flux has been measured with high precision, and SK has set stringent limits on potential periodic variations to reaffirm the stability of the solar core. With gadolinium doped since SK-VI to tag the spallation backgrounds more efficiently, it is promising that SK would provide new physics results, such as hep flux limit.
Speaker: Yiyang Wu (Tsinghua University) -
118
Measurement of Solar Boron-8 Neutrinos via Coherent Elastic Neutrino-Nucleus Scattering with XENONnT
The XENONnT experiment at the INFN Laboratori Nazionali del Gran Sasso aims to detect dark matter candidates—Weakly Interacting Massive Particles (WIMPs)—by observing their interactions with xenon nuclei. An especially intriguing aspect of this search is the potential observation of coherent elastic neutrino-nucleus scattering (CEvNS) from Boron-8 solar neutrinos, which can mimic WIMP signals. In this talk, I will present a search for solar neutrinos via CEvNS using recent XENONnT data, highlighting the detector performance, signal and background modeling, and the statistical methods employed.
Speaker: Ms Kexin Liu (Tsinghua University) -
119
Progress of solar pp neutrino search with XENONnT
The XENONnT experiment, located at Laboratori Nazionali del Gran Sasso (LNGS), is a dark matter experiment using a dual-phase time projection chamber with 8.5 tonnes of xenon. Solar neutrinos, dominated by the proton-proton (pp) neutrinos, can scatter elastically with electrons and produce electronic recoils (ER) detectable to XENONnT down to the keV scale. The ER background in XENONnT has been suppressed to an extremely low level by reducing the radioactive Rn-222 and Kr-85 backgrounds. In this talk, I will present the progress towards the first measurement of solar pp neutrinos with XENONnT.
Speaker: Prof. Jingqiang Ye (The Chinese University of Hong Kong, Shenzhen) -
120
Measuring 40Ar-solar neutrino charged-current interactions in the DEAP-3600 dark matter detector
The DEAP-3600 dark matter detector, located 2 km underground at SNOLAB, has 3.3 tonnes of liquid argon (LAr) and initially began data collection in 2016. Due to its ultra-low backgrounds and large exposure, the DEAP-3600 detector is sensitive to charged-current interactions from $^8$B solar neutrino absorbing on $^{40}$Ar. While this reaction has never been measured before, it offers large LAr experiments powerful sensitivity to solar and supernova neutrinos. Due to a Fermi transition and several Gamow-Teller transitions, this reaction has an unusually high cross section for charged-current neutrino-nucleus interactions, and reactions passing through an excited state of the daughter $^{40}$K nucleus provide a channel that separates it from background. In this talk, we will present the current status of this search in DEAP-3600, the experimental challenges that must be overcome to observe it, and exciting physics that it can probe.
Speaker: Shawn Westerdale (University of California, Riverside) -
121
Search for neutron decay into an antineutrino and a neutral kaon in Super-Kamiokande
Some models in supersymmetric grand unified theories (SUSY GUTs) predict baryon number violating neutron decay into an antineutrino and a neutral kaon ($n \rightarrow \bar{\nu} K^0$). In this presentation, we report on a search for this neutron decay mode using 0.401 megaton·years of data collected by the Super-Kamiokande detector, which corresponds to 4.4 times the exposure of the previous analysis. The sensitivity has been improved by enhancing the momentum reconstruction of charged pions from $K^0$ decays and performing a fit to the invariant mass distributions. No statistically significant signal excess above the expected background was observed. Consequently, a lower limit on the partial lifetime was set at $7.8 \times 10^{32}$ years at a 90% confidence level, which improves upon the previous limit by a factor of six. This result places the most stringent constraint on the $n \rightarrow \bar{\nu} K^0$ decay mode to date.
Speaker: Koki Yamauchi (Tokyo University of Science)
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117
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Underground Laboratories: parallel session 3 North Hall #3
North Hall #3
Convener: Yeongduk Kim (Institute for Basic Science)-
122
Th and U assessment in high-purity copper for low-background applications at CUP
High-purity copper is an ideal material for constructing ultra-low background radiation measurement detectors. Experiments involving rare nuclear decay, such as neutrinoless double beta decay, and searches for dark matter often require construction materials with bulk and surface radioactivity levels below 10-12 g/g of Th/U level. Electroformed copper offers advantageous mechanical, electrical, and thermal properties, and it has an intrinsically low level of primordial radioisotopes, thorium (Th) and uranium (U). However, current experiments utilizing detector components made from high-purity electroformed copper face challenges due to surface contamination that occurs during the machining of the detector units. Many low-background experiments that use high-purity copper have indicated that this surface contamination becomes the primary source of background interference. Utilizing extractive chromatography sample preparation followed by ICP-MS detection at CUP, we developed a Th and U method assessment at 10-13 g/g of Th/U in bulk copper and at 10-12 g/g of Th/U in surface. With this technique, we tested the purity of various copper samples and the purity of the Cu surface produced with different machining methods, such as milling and threading. Also, the thickness of the contaminated surface was examined to perform a proper surface cleaning. The obtained results of our copper radiopurity campaign will be discussed in the presented talk.
Speaker: Olga Gileva (Center for Underground Physics at the Institute for Basic Science) -
123
Ultra-trace Th and U Measurements in Metals with Inductively Coupled Plasma Mass Spectrometry（ICP-MS）
This study established an optimized protocol employing quadrupole inductively coupled plasma mass spectrometry (ICP-QMS) with internal standard calibration to achieve direct ultratrace ²³⁸U and ²³²Th radionuclides quantification. Cross-validation with high-purity germanium gamma spectroscopy (HPGe) confirmed the method’s reliability. Systematic ICP-QMS screening of industrial materials established the current baseline radioactivity in stainless steel and titanium metals. Through UTEVA resin enrichment, ²³²Th and ²³⁸U in copper were quantified at μBq/kg-level radioactivity. Impurity profiling across smelting stages demonstrated vacuum electron beam smelting's exceptional purification efficacy.
Speaker: Yan Zhu (Shanghai Jiao Tong University) -
124
Application of the bateman equation to analyze disequilibrium in the $^{232}$Th and $^{238}$U chains in low-background detector materials
ABSTRACT
In rare-event search experiments such as AMoRE and COSINE, estimating background radioactivity levels and identifying background sources are crucial for background reduction. Typically, isotopes in the $^{238}$U and $^{232}$Th decay chains with relatively short half-lives are grouped together, and secular equilibrium is assumed during background measurements and estimations. During our material screening process, we observed that the $^{228}$Ac–$^{228}$Th, and $^{238}$U-$^{226}$Ra secular equilibrium was disrupted in several candidate materials. These measurements were conducted using a single HPGe detector at Y2L before 2023, and at Yemilab from 2024 onward.
In one notable case, an aluminum sample showed a significant increase in $^{226}$Ra activity—from below the detection limit (22 mBq/kg) in 2021 to 893 ± 48 mBq/kg in 2025—despite the fact that there was no treatment or exposure that could have lead to radium contamination of the sample. Interestingly, the $^{234}$Th activity remained nearly constant at around 60 Bq/kg, indicating that the $^{238}$U parent activity did not change. Moreover, the $^{228}$Th/$^{228}$Ac activity ratio decreased significantly over time. In 2021, the activity values were $^{228}$Ac = 155 ± 19 mBq/kg and $^{228}$Th = 4030 ± 206 mBq/kg, resulting in a ratio of approximately 27. By 2025, the measured values had shifted to $^{228}$Ac = 421 ± 30 mBq/kg and $^{228}$Th = 1273 ± 67 mBq/kg, corresponding to a reduced ratio of around 3.
This behavior suggests that prior radium purification influenced the relative amounts of isotopes in both the $^{238}$U and $^{232}$Th decay chains, resulting in a significant disruption of secular equilibrium.
A clear correlation was observed between the buildup of $^{226}$Ra and the imbalance in the $^{228}$Th/$^{228}$Ac activity ratio, highlighting the interconnected nature of these decay series.
These findings underscore the need for time-dependent modeling using the Bateman equation, which can account for such disequilibrium and provide accurate predictions of future activity levels.By applying this method, we aim to predict the time-dependent activity of long-lived isotopes and enhance the accuracy of background level estimation in upcoming rare-event search experiments, including AMoRE-II and COSINE.
Speaker: Eunkyung Lee (Center for Underground Physics, IBS) -
125
Simulation of the background from $^{13}$C($\alpha$, $n$)$^{16}$O reaction in the JUNO scintillator
The Jiangmen Underground Neutrino Observatory (JUNO) is a next generation neutrino detector. The experiment will begin data collection this year. Its main and ultimate goal is to determine the neutrino mass ordering. To achieve this fundamental milestone, the precise reactor antineutrino energy spectrum must be extracted. Therefore, detailed knowledge of all relevant backgrounds in the liquid scintillator target is mandatory. Antineutrinos are detected through the inverse beta decay reaction in liquid scintillator. One possibly significant background for the measurements can arise from ($\alpha$, $n$) reactions. These occur on $^{13}$C nuclei due to the presence of residual radioactive impurities, primarily, $^{238}$U, $^{232}$Th, $^{210}$Pb/$^{210}$Po and their daughters. This work describes the simulation of this background, performed using the open source Geant4-based software SaG4n, a new event generator and JUNO’s detector response simulation package. Each stage of the ($\alpha$, $n$) reaction is considered, including the $\alpha$ particle propagation in the medium until the ($\alpha$, $n$) interaction and emission of a neutron and de-excitation particles from the excited states of the final nucleus. Expected ($\alpha$, $n$) background event rates and respective energy spectra have been obtained for all $\alpha$ particle sources ($^{238}$U and $^{232}$Th chains and $^{210}$Pb/$^{210}$Po), considering JUNO's predicted radioactivity concentration. Corresponding uncertainties are also evaluated. It is important to note that the background from $^{13}$C($\alpha$, $n$)$^{16}$O reaction may influence geoneutrino sensitivity in JUNO. The framework and results presented here are relevant for other organic liquid scintillator neutrino detectors and may be useful in direct detection dark matter experiments.
Speaker: Maxim Gromov (SINP MSU, JINR) -
126
K-42 mitigation studies in Ar-42-spiked liquid argon for LEGEND
The LEGEND experiment aims to detect neutrinoless double beta decay (0νββ) of Ge-76 using high-purity germanium (HPGe) detectors immersed in liquid argon (LAr). The LAr serves both as a coolant and as an active shield against background radiation. In the current phase (LEGEND-200), HPGe detectors are operated in conventional atmospheric LAr, which contains the cosmogenically activated radioactive isotope Ar-42. K-42, the beta-decaying progeny of Ar-42 (Qβ = 3.5 MeV), is a major background component of LEGEND-200.
LEGEND-1000 aims to use underground LAr (UGLAr) depleted in Ar-42 to eliminate this background. In case UGLAr is unavailable, K-42 would be the dominant background at the 0νββ Q-value (2.039 MeV) due to beta-decay-induced events occurring on the surface of the HPGe detectors. These surface events must be suppressed and efficiently discriminated from 0νββ candidate events. We present K-42 suppression measurements conducted at the SCARF LAr test facility at TU-Munich using Ar-42-enriched LAr. Our study evaluates background discrimination methods, including analyzing event topologies in HPGe detectors and using scintillation light readout from LAr for suppression. Additionally, we explore enhancing suppression by surrounding the detectors with optically active barriers, such as polyethylene naphthalate (PEN) enclosures and tetraphenyl butadiene (TPB) coated nylon mini-shrouds, and present preliminary results. This research is funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - Excellence Cluster ORIGINS EXC 2094-39078331; SFB1258-283604770.Speaker: Christoph Vogl (TU-Munich)
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122
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Coffee break International Conference Center
International Conference Center
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Dark Matter and Its Detection: parallel session 4A Conference Room F2-R1
Conference Room F2-R1
Convener: Shin Ted Lin-
127
Search of light Dark Matter with TESSERACT experiment at Laboratoire Souterrain de Modane
TESSERACT (Transition Edge Sensor with Sub-Ev Resolution and Cryogenic Targets) is an experiment lead by American, French and Swiss teams aiming at looking for Light Dark Matter in the Laboratoire Souterrain de Modane.
Several cryogenic targets will be used in order to be sensitive to different DM interactions, allowing to explore both Electronic Recoils Dark Matter (ERDM) and Nuclear Recoils Dark Matter (NRDM) in the sub-GeV range, down the keV scale
Each of these targets are also designed to mitigate the so-called Low Energy Excess, a background from unknown source seen by every low-threshold cryogenic experiment. The three detector technologies are HeRALD, a superfluid Helium experiment, SPICE, using polar crystal, and Ge/Si bolometers. These detectors will be equipped with Transition Edge Sensor cooled at 14 mK, allowing to reach very low energy thresholds.
In this presentation, I will make an overview of the TESSERACT technologies, talk about the recent improvements, and make an emphasis on the Ge bolometer that is currently being developped in France, that has the specificity to assess both heat and ionization. Thanks to this double measurment, at low voltage we are able to take advantage of the Ionization yield to discriminate electronic recoils and nuclear recoils, and at high voltage to boost the heat signal to reach a single phonon resolution.Speaker: Paul Vittaz (CNRS - IP2I) -
128
The PICO-40L Dark Matter Search
The PICO Collaboration uses bubble chamber technology for direct-detection searches of Weakly-Interacting Massive Particles (WIMP). Filled with superheated C$_3$F$_8$, the thermodynamic threshold of PICO detectors can be set such that the detectors are optimised for dark matter detection while being insensitive to gammas from electron recoils. The presence of fluorine atoms in the C$_3$F$_8$ gives PICO the potential to set world-leading exclusion limits for spin-dependent WIMP-proton interactions. PICO-40L is currently operating 2 km underground at SNOLAB in Sudbury, Ontario, Canada. It is the first large-scale implementation of the "right-side up" bubble chamber design, in which the absence of a buffer fluid in contact with the C$_3$F$_8$ minimises background rates from particulates entering the chamber. It acts as a proof-of-concept for the next generation PICO-500 detector, a 260-L bubble chamber with a projected ton-year exposure currently in the assembly phase at SNOLAB. This talk will present the status of the PICO-40L detector as well as an overview of preliminary analyses of PICO-40L data.
Speaker: William Woodley (University of Alberta) -
129
The CYGNO experiment, a Gaseous TPC for directional Dark Matter searches
The CYGNO/INITIUM project introduces an innovative approach to directional Dark Matter detection using a gaseous Time Projection Chamber (TPC). Targeting low mass (0.5-50 GeV) WIMPs-like Dark Matter, the experiment uses a He/CF4 gas mixture sensitive to both spin-dependent and spin-independent interactions at atmospheric pressure with optical readout. Building on the success of our 50 L prototype, LIME, we aim to deploy a 0.4 m³ demonstrator, CYGNO04, at Laboratori Nazionali del Gran Sasso (LNGS) between 20245 and 2026 to validate the technology's performance and scalability.
In CYGNO detectors, particle interactions ionize the gas, creating electrons that drift to the amplification stage, consisting of three Gas Electron Multipliers (GEMs). The readout system combines a scientific CMOS (sCMOS) camera and Photomultiplier Tubes (PMTs) to detect light produced during electron avalanches. This light is captured in a two-dimensional (X-Y) projection by the sCMOS camera and a time profile (dZ) by the PMTs, enabling 3D reconstruction of ionizing events. High granularity and rapid response allow detailed energy deposition mapping, supporting topology, directional, and head-to-tail recognition.
Results from LIME, which conducted data taking at the underground LNGS labs, show significant advancements in particle identification and 3D tracking capabilities.
Recent progress on the CYGNO-04 status will be presented, highlighting its role in the project's future. The CYGNO/INITIUM project will contribute substantially to Dark Matter detection, and the possibility that this same detector could perform neutrino measurements sets the stage for future large-scale experiments.Speaker: Davide Fiorina (GSSI and INFN) -
130
Overview of the Axion Dark Matter eXperiment
The QCD axion is a natural solution to the strong CP problem, making it one of the most well-motivated dark matter candidates. Using dilution refrigerators and quantum amplifiers, the Axion Dark Matter eXperiment (ADMX) has reached to the benchmark models of QCD axion dark matter: Kim–Shifman–Vainshtein–Zakharov (KSVZ) and Dine–Fischler–Srednicki– Zhitnitsky (DFSZ). I will give an overview on the current status of the ADMX main experiment and other R&D projects for high-mass axion search.
Speaker: Dan Zhang (University of Washington) -
131
The MADMAX experiment: First dark matter constraints and the road ahead
The QCD axion is a well-motivated hypothetical particle that simultaneously addresses the strong CP problem and constitutes a compelling cold dark matter candidate. The MADMAX experiment (Magnetized Disk and Mirror Axion Experiment) is designed to search for axions in the mass range of 40–400 μeV by boosting the microwave radiation in the range of 10-100 GHz induced by the inverse Primakoff effect in a dielectric haloscope. Recently, MADMAX has achieved significant milestones, including the publication of its first search results for axion-like particles and dark photons. The collaboration is now focused on preparations for the first cryogenic measurements using an open booster configuration. In this talk, I will present an overview of the MADMAX experiment, summarize the recent results, and outline the upcoming steps toward a full-scale axion search.
Speaker: Juan Pablo Arcila Maldonado (Max Planck Institute for Physics) -
132
Background simulation for the dark matter search experiment CRESST
Cryogenic Rare Event Search with Superconducting Thermometers (CRESST) is a direct detection dark matter (DM) search experiment located at the Laboratori Nazionali del Gran Sasso in Italy. Utilizing cryogenic and scintillating crystals, CRESST searches for nuclear recoils from DM particles, and has repeatedly achieved threshold below 100 eV across a variety of target materials. However, at these energies, the ability to discriminate between potential DM signals and electromagnetic background is limited. In addition, a key challenge shared by all low-mass dark matter searches — including CRESST — is the existence of unknown event populations at very low energies known as the low energy excesses. Therefore, having a reliable background model is of utmost importance.
To address this, a comprehensive GEANT4-based simulation framework (ImpCRESST) was developed, continuously refined to reflect the current configuration and materials of CRESST’s detector modules, used to understand various background components in the measured spectra by CRESST and development of the background model.
The CRESST background model and the ImpCRESST simulation code will be presented and discussed in detail.Speaker: Valentyna Mokina -
133
Investigating Ultra-Low Energy Ionization Yield from Nuclear Recoils in Semiconductor Detectors via Molecular Dynamics Simulations
Nuclear recoil ionization yield constitutes a critical uncertainty source in low-energy detection for dark matter (DM) and coherent elastic neutrino-nucleus scattering (CEvNS) experiments. We present a novel methodology employing molecular dynamics simulations to assess ionization yields in crystalline semiconductor detectors. This non-parameterized approach resolving inherent limitations of traditional Lindhard model through explicit incorporation of crystal condensed matter effects, facilitating a seamless reliability from high-energy (>10 keV) to electron-hole pair (EHP) regimes. Our model achieves the best agreement with experimental data in silicon to date, especially at the minimal energy level of a single EHP. Meticulously consideration of ion transport mechanisms reveals fundamental ionization yield distributions, superseding conventional single-value models. The distributional paradigm extends the DM-nucleon elastic scattering exclusion limit to 0.29 GeV/c² under single-EHP sensitivity. We further report advancements in modeling quantum effects and channeling phenomena affecting ionization yields in high-purity germanium detectors.
Speaker: Mr Chang-Hao Fang (Sichuan University)
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127
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Gravitational Waves: parallel session 4 Conference Room F1-R3
Conference Room F1-R3
Convener: Jun Zhang (University of Chinese Academy of Sciences)-
134
Implications of Cosmological Gravitational Wave Sources for Fundamental Physics
Advances in gravitational wave detection offer a new approach to probing the very early history of the Universe and the corresponding fundamental physics models. They can provide crucial insights into topics such as symmetry breaking, gravitational theories, and the origin of dark matter. This presentation will briefly introduce and summarize the primary sources of gravitational waves, including processes like primordial scalar perturbations, topological defects, preheating, and first-order phase transitions. These sources offer probes or constraints on fundamental physics and cosmic evolution through various means, such as their gravitational wave energy spectrum, anisotropy, and the induced curvature perturbations and dark matter associated with them.
Speaker: Jing Liu -
135
Probing Dark Matter with Space and Ground-based Gravitational Waves Detectors
Dark matter makes up most of the matter in the universe, yet its true nature remains unknown. Gravitational wave observations open up new opportunities to search for dark matter in ways not possible before. In this talk, I will present two efforts to explore dark matter using both ground- and space-based gravitational wave detectors. First, I will introduce searches for planetary-mass compact objects in so-called "mini-EMRI" systems using data from ground-based detectors. These sub-solar mass objects are most likely to be primordial black holes—formed in the early universe—and represent a viable candidate for dark matter. Second, I will highlight the potential of future space-based detectors to probe ultralight dark matter, focusing in particular on spin-2 fields. Together, these approaches demonstrate how gravitational wave astronomy can offer fresh insights into the dark matter puzzle.
Speaker: Ju Chen -
136
Bayesian model selection of Primordial Black Holes and Dressed Primordial Black Holes with lensed Gravitational Waves
If particle dark matter (DM) and primordial black holes (PBHs) coexist, PBHs will be surrounded by particle DM, forming celestial objects known as dressed PBHs (dPBHs). These structures suggest a scenario in which PBHs and DM can exist simultaneously. However, in the high-frequency regime, the gravitational lensing effect of bare PBHs is similar to that of dPBHs. Ground-based gravitational wave (GW) detectors are particularly sensitive to high-frequency GW signals. In this regime, the lensing effect of a point-mass lens with a mass in the range of $10^{-1} \sim 10^2 M_{\odot}$ becomes significant. In this work, we incorporate dPBH models with GW observations and employ Bayesian inference techniques to distinguish PBHs from dPBHs. Using the third-generation ground-based GW detectors, Einstein Telescope (ET) and Cosmic Explorer (CE), as examples, we demonstrate that these detectors can effectively differentiate the lensing effects of dPBHs from those of PBHs across a broad frequency range. Furthermore, we find that with a larger black hole (BH) mass inside the surrounding particle DM, ET and CE can distinguish these two lensed models with even greater precision.
Speaker: Dr Xin-yi Lin (Beijing Normal University)
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134
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High-Energy Astrophysics and Cosmic Rays: parallel session 4 Conference Room F1-R2
Conference Room F1-R2
Convener: Kazuyoshi Kobayashi (Waseda university)-
137
Latest Results from the Alpha Magnetic Spectrometer on the International Space Station
The Alpha Magnetic Spectrometer (AMS) is a precision particle physics detector operating on the International Space Station. Since 2011, AMS has collected more than 250 billion charged cosmic rays, from elementary particles to iron nuclei with energies up to multi-TeV. The high-precision measurements with ~1% accuracy, over a solar cycle, have led to many surprising observations. The latest results on cosmic elementary particles (electrons, positrons, antiprotons, and protons) reveal unique properties and indicate new sources of particles and antiparticles. The data on nuclei and isotopes exhibit characteristic energy dependences that are not explained by current theories. The comprehensive AMS data requires a new model of the cosmos.
Speaker: Vitaly Choutko -
138
Highlights of LHAASO Cosmic Ray Energy Spectrum and Composition Measurements
The Large High-Altitude Air Shower Observatory (LHAASO) is a hybrid detector experiment, including one square kilometer array of scintillator detectors and muon detectors, a 78,000 square meter water Cherenkov detector array and 18 wide field of view Cherenkov telescopes. This multi-parameter observation of air showers enables LHAASO to measure the energy spectrum and composition of individual cosmic ray elements with high resolution, providing a unique opportunity to explore the origin, acceleration, and propagation of high-energy cosmic rays. In this presentation, we will focus on the main results regarding the energy spectra of protons, helium, the combined spectrum of proton and helium, and the all-particle spectrum in the knee region as accurately measured by LHAASO.
Speaker: Dr 玲玲 马 (中国科学院高能物理研究所) -
139
Properties of Cosmic Deuteron Flux
Precision measurements by the Alpha Magnetic Spectrometer (AMS) on the International Space Station of the deuteron (𝐷) flux are presented. The measurements are based on 21 million 𝐷 nuclei in the rigidity range from 1.9 to 21 GV collected from May 2011 to April 2021. We observe that over the entire rigidity range the 𝐷 flux exhibits nearly identical time variations with the 𝑝, 3He , and 4He fluxes. Above 4.5 GV, the 𝐷/4He flux ratio is time independent and its rigidity dependence is well described by a single power law ∝𝑅^Δ with Δ𝐷/4He =−0.108±0.005. This is in contrast with the 3He/4He flux ratio for which we find Δ3He/4He =−0.289±0.003. Above ∼13 GV we find a nearly identical rigidity dependence of the 𝐷 and 𝑝 fluxes with a 𝐷/𝑝 flux ratio of 0.027 ±0.001. These unexpected observations indicate that cosmic deuterons have a sizable primarylike component. With a method independent of cosmic ray propagation, we obtain the primary component of the 𝐷 flux equal to 9.4 ±0.5% of the 4He flux and the secondary component of the 𝐷 flux equal to 58±5% of the 3He flux.
Speaker: Weiwei Xu (Shandong University) -
140
Unique Properties of Primary Cosmic Rays: Results from the Alpha Magnetic spectrometer
We present high statistics measurements of primary cosmic rays nuclei p to Ni based on 13.5 Years AMS data.The systematic comparison with the latest GALPROP cosmic ray model is presented.
Speaker: Qi Yan (IHEP, CAS) -
141
Unique Properties of the 3rd group of cosmic rays: Results from the Alpha Magnetic Spectrometer
We report the latest results on the properties of C, N, Ne, Na,Mg, Al, S, Cl, Ar, K, and Ca cosmic rays fluxes in the rigidity range 2.5 GV to 3 TV collected by the AMS furing first 13.5 years of operation. We observe that fluxes are well described by the sums of a primary cosmic ray component and a secondary cosmic ray component. With our measurements, the abundance ratios at the source C/O, N/O, Ne/Si, Na/Si, Mg/Si, Al/Si, S/Si, Cl/Si, Ar/Si, K/Si, and Ca/Si are determined independent of cosmic ray propagation.
Speaker: 诚 张 (中国科学院高能物理研究所) -
142
Anisotropy of Elementary Particles with the Alpha Magnetic Spectrometer on the ISS
Analysis of anisotropy of galactic positrons, electrons and protons has been performed with the Alpha Magnetic Spectrometer on the International Space Station. This measurement allows to differentiate between point-like and diffuse sources of cosmic rays for the understanding of the origin of high energy positrons or the hardening in the proton flux. The AMS results of the dipole anisotropy of elementary particles are presented along with the discussion of the implications of these measurements.
Speaker: Prof. Vladimir Mikhailov (SDIAT) -
143
Determine the origin of cosmic rays from precise measurements of cosmic ray spectrum and mass
we show how the precise measurement of cosmic ray spectrum by AMS02, DAMPE, HAWC, LHAASO, TUNKA and AUGER can give very strong constraints on the components of galactic and extra-galactic cosmic rays and give important implications on the origin of cosmic rays.
Speaker: Xiaojun Bi
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137
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Neutrino Physics and Astrophysics: parallel session 4A North Hall #1
North Hall #1
Convener: Steven Biller (Oxford University)-
144
The Way Forward for Neutrinoless Double Beta Decay Using Liquid Xenon
Abstract: The search for neutrinoless double beta decay is a very high priority for the astroparticle physics community. In this note I will argue that the focus of new facilities for this search should be aimed at reaching the bottom of the normal hierarchy band. I will focus on ways in which current liquid xenon experiments might achieve the required energy and spatial resolutions to achieve the required background levels. The realities of the world xenon production capabilities imply that this project should be done as a global initiative and the best time to build such collaborative effort is now when everyone can contribute to the development of the design.
Speaker: David Sinclair (Carleton University) -
145
Search for Double Beta Plus Decays with NuDoubt++
Double beta plus decay is a rare nuclear disintegration process. Difficulties in its measurement arise from suppressed decay probabilities, experimentally challenging decay signatures and low natural abundances of suitable candidate nuclei. In this presentation, we propose NuDoubt++, a new detector concept to overcome these challenges. It is based on the first-time combination of hybrid and opaque scintillation detector technology paired with novel light read-out techniques. This approach is particularly suitable detecting positron (beta plus) signatures. We expect to discover two-neutrino double beta plus decay modes within 1 tonne-week exposure and are able to probe neutrinoless double beta plus decays at several orders of magnitude improved significance compared to current experimental limits.
Speaker: Stefan Schoppmann (JGU Mainz) -
146
Sensitivity of the CUPID experiment to $0\nu\beta\beta$ decay of $^{100}$Mo
CUPID is a next-generation bolometric experiment to search for neutrinoless double-beta decay ($0\nu\beta\beta$) of $^{100}$Mo using Li$_2$MoO$_4$ scintillating crystals. It will operate at $\sim$10 mK in the existing CUORE cryostat at the Laboratori Nazionali del Gran Sasso in Italy. Each crystal will be facing two Ge-based bolometric light detectors for $\alpha$ rejection. In this work, we develop a statistical analysis, in a Frequentist and a Bayesian framework, to compute the discovery and the exclusion sensitivity of CUPID to the $0\nu\beta\beta$ half-life and to the effective Majorana neutrino mass. This computation is done numerically based on pseudo-experiments. We evaluate the sensitivity for various background indices and energy resolution. For the CUPID baseline scenario, with a background and an energy resolution of $1.0 \times 10^{-4}$ counts/keV/kg/yr and 5 keV FWHM at the Q-value, respectively, this results in a Bayesian exclusion sensitivity at 90% confidence interval of $\hat{T}_{1/2} > 1.6^{+0.6}_{-0.5} \times 10^{27} \ \mathrm{yr}$, corresponding to the effective Majorana neutrino mass of $\hat{m}_{\beta\beta} < \ 9.6$ -- $16.3 \ \mathrm{meV}$. In the Frequentist analysis, we obtain a discovery sensitivity at 3$\sigma$ of $\hat{T}_{1/2}= 1.0 \times 10^{27} \ \mathrm{yr}$, corresponding to $\hat{m}_{\beta\beta}= \ 12.2$ -- $20.6 \ \mathrm{meV}$.
Speaker: Pia Loaiza (IJCLab, IN2P3/CNRS Université Paris-Saclay) -
147
Status of the NvDEx experiment
The No neutrino Double-beta-decay Experiment (NvDEx) is designed to search for the neutrinoless double-beta decay using a high-pressure 82SeF6 gas time projection chamber (TPC) and read out by low-noise CMOS sensor chips. Combining the advantages of the high Q value of 82Se and TPC's ability to distinguish double beta decay signal and background using event topology, NvDEx is expected to achieve a very low background level. This talk will report the concept and current status of the NvDEx experiment.
Speaker: Dr Hao Qiu -
148
Search for Double Beta Decay Modes of 134Xe with EXO-200 Phase-II
Neutrinoless double beta (0νββ) decay offers a means to explore whether neutrinos are massive Majorana fermions, i.e., their own antiparticles, and thus a portal between matter and antimatter. The EXO-200 experiment operated between 2011 and 2018 at the WIPP underground site in New Mexico, USA, setting some of the strongest constraints on the existence of this decay in 136Xe. EXO-200 was a single-phase liquid xenon time projection chamber (LXe TPC) and used 200 kg of isotopically enriched liquid xenon (LXe) with 80% 136Xe and 20% 134Xe. 134Xe, another double beta emitter with a Q energy of 825 keV, provides an opportunity to search for 0νββ decay with a second isotope of the same element within one detector, which allows to reduce uncertainties on the ratio of the decay probabilities. We present a search for double beta decay modes of 134Xe with the EXO-200 Phase II dataset (2016-2018) featuring improved sensitivity with respect to a similar study performed with the Phase I run.
Speaker: Thomas Brunner -
149
CUPID-CJPL: a cryogenic bolometer testbed
The search for the neutrinoless double beta decay has particular meanings for answering the essential question about Majorana property of neutrinos. CUPID collaboration chose the crystal of Lithium molybdate with enriched 100Mo as the source and target to explore this important decay. The high Q value of 100Mo and the scintillation property of this crystal enable CUPID to reach a superior low background level. The radioactivity of the crystals is crucial. We plan to build a cryogenic bolometer testbed in Jinping underground lab, to precisely measure the radioactivity from the crystals made by Shanghai Institute of Ceramics，Chinese Academy of Sciences（SICCAS）. This testbed could also pave the road to explore new physics using cryogenic bolometer in Jinping underground lab.
Speakers: Hao Chen (Fudan University), Long Ma (Fudan University) -
150
The NEXT-100 experiment
Searches for neutrinoless double-beta decay (0νββ) represent one of the most promising avenues for uncovering new frontiers in particle physics, particularly in understanding the true nature of the neutrino.
The Neutrino Experiment with a Xenon TPC (NEXT) investigates neutrinoless double-beta decay (0νββ) in $^{136}$Xe using high-pressure Xenon time projection chambers. The key technologies of the NEXT include a photomultiplier tube (PMT) plane in correspondence of the cathode for precise energy measurement, and a silicon photomultiplier (SiPM) plane at the anode for detailed tracking of event topology.
Another key feature of the NEXT is the production of secondary light via electroluminescence from drifted electrons as they reach the anode plane. This approach enables excellent energy resolution, and combined with the detection of the primary scintillation light, allows for the measurement of the absolute z-position of the track.The NEXT-100 experiment, holding up to 100 kg of Xenon at 15 bar, is currently under commissioning at the Canfranc Underground Laboratory. It has demonstrated an O(10 ms) electron drift time, much longer than the maximum drift time, and achieved an energy resolution better than 5% FWHM at 42 keV using $^{83m}$Kr decays. After three years of data taking, it is expected to reach a half-life sensitivity >10$^{25}$ years, with a background rate of ~ one count per year within the region of interest. In the future, NEXT-HD based on the technique developed in NEXT-100 with 1 ton of enriched Xenon is expected to reach a sensitivity >10$^{27}$ y in less than 5 years of data taking. Moreover in the context of a ton scale detector, the implementation of the barium tagging technique might lead to zero background operation, making NEXT one of the leading detector in the search of the 0νββ decay.
In this talk an overview of the NEXT experiment with particular focus on NEXT-100 and the path towards a ton scale detector will be given.
Speaker: Samuele Torelli (Donostia International Physics Center)
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144
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Neutrino Physics and Astrophysics: parallel session 4B North Hall #2
North Hall #2
Convener: Qun Wu (Shandong University)-
151
Latest neutrino oscillation measurements from T2K
T2K is a long-baseline neutrino oscillation experiment, measuring the oscillation of neutrinos and antineutrinos produced at J-PARC facility which then travel 295 km across Japan to its far detector, SuperKamiokande. T2K has been taking data since 2009 and sets world-leading constraints on many neutrino oscillation parameters within the standard PMNS three-flavour mixing paradigm, including offering hints that the CP-violating phase (dcp) favours non CP-conserving values. In this talk, T2K’s latest analysis of neutrino oscillations will be presented. This analysis includes the presence of new and improved event samples at the near and far detectors as well as a significant update to the treatment of systematic uncertainties on neutrino interactions and the near detector response. Prospects for future analyses with significantly improved statistics, thanks to an increasing beam power, and the use of T2K’s newly installed near detector upgrade will also be shown.
Speaker: Masaki Ishitsuka (Tokyo University of Science) -
152
Physics potential of detecting solar neutrinos at JUNO
JUNO (Jiangmen Underground Neutrino Observatory) is a neutrino experiment under construction in China. It will be the largest liquid scintillator experiment, detecting neutrinos and anti-neutrinos by using 20 kton of organic liquid scintillator contained in an huge acrylic vessel of 35 m diameter. The experiment will start data taking the data-taking in 2025 with the main goal to determine the Neutrino Mass Ordering (NMO).
Thanks to its very large mass, low backgrounds and unprecedented energy resolution JUNO will be a pioneering experiment in neutrino physics. JUNO will reach the sensitivity to NMO in six years of data-taking, but it will be potentially a powerful detector also for solar neutrinos.
Solar neutrinos are produced by nuclear reactions burning in the core of the Sun. The main mechanism of hydrogen burning in the Sun is the pp chain. Five reactions of this chain produce neutrinos (pp, pep, hep, $^8\mathrm{B}$, $^7\mathrm{Be}$). Furthermore a small fraction ($1\%$) of solar neutrinos comes from the CNO-cycle. Several questions remain open for solar physics, which would require an improved measurement of the solar neutrino flux, for example the so-called “solar metallicity problem”.
Radioactivity is the main background for a solar neutrino flux measurement. The radioactive backgrounds in JUNO will be due to the natural isotopes belonging to the $^{238}\mathrm{U}$ and $^{232}\mathrm{Th}$ chains and to $^{40}\mathrm{K}$, but also to the anthropogenic isotope Kr, and the cosmogenic ones, produced by residual cosmic muons interacting with of the liquid scintillator.
I will present a Monte-Carlo study of the sensitivity of JUNO to solar neutrinos both from pp-chain and CNO cycle.Speaker: Marco Beretta (INFN - University of Milano) -
153
Research and Development of Jinping Neutrino Experiment
The Jinping Neutrino Experiment (JNE), situated in the world's deepest underground laboratory, the China Jinping Underground Laboratory (CJPL), conducts research on solar neutrinos, geo-neutrinos, supernova neutrinos, and neutrinoless double beta decay. The Jinping Neutrino one-ton prototype, located in CJPL-I, has completed measurements of cosmic rays and background. Next, JNE plans to build a multi-hundred-ton neutrino detector in CJPL-II by the end of 2026. Using simulations, we've optimized the detector's geometry and finished structural design. The excavation of the foundation pit in D2 Hall of CJPL-II is completed. The detector will use new 8-inch MCP-PMTs, undergoing tests; self-developed ADC has been tested on the one-ton prototype. Oil and water-based slow liquid scintillators (SLSs) are developed. We have also developed reconstruction algorithms for SLSs, enabling particle identification of electrons, gamma rays, and protons in the several MeV energy range.
Speaker: Benda Xu (Tsinghua University) -
154
Detecting Solar Neutrinos and Fermionic Dark Matter with $^{136}$Xe in nEXO
Thanks to recent observations of low-lying isomeric states in the nuclear structure of $^{136}$Cs, charged-current interactions in liquid xenon (LXe) time projection chambers (TPCs) of the form $\nu_e + ^{136}$Xe are expected to cause a time-delayed coincident signal in the scintillation channel which can be used to for background rejection on the order of $10^{-9}$ which is more than sufficient to reject the dominant 2vbb background and operate in a background free regime. In this presentation, we will discuss how nEXO, a proposed 5 tonne enriched LXe TPC designed to search for neutrinoless double beta decay, can use this detection channel to extend its scientific program to include solar neutrinos and fermionic dark matter. In the case of solar neutrinos, we find that nEXO can expect to measure the CNO neutrino flux on earth with comparable precision to Boreixno’s world leading measurement, and to improve the measurement of the $^7$Be line-shift by an order of magnitude. In regards to fermionic dark matter, we find that nEXO could both extend the sensitivity of LXe TPCs to lower masses, as well as to increase searchable parameter space by more than three orders of magnitude.
Speaker: Glenn Richardson (Yale University, SLAC National Lab) -
155
Detecting Solar neutrinos with the CYGNO gas TPC
The CYGNO project aims to develop a gaseous high-precision Time Projection Chamber with an optical readout for directional Dark Matter searches and solar neutrino spectroscopy. CYGNO incorporates innovative features, such as the utilization of a He-CF4 scintillating gas mixture, and an optical readout made by PMTs and scientific CMOS (sCMOS) cameras.
Directional Dark Matter (DM) detectors, as high precision gaseous TPCs, are not only able to discriminate solar neutrinos interacting through Coherent Elastic Neutrino-Nucleus Scattering (CEvS) from a DM signal, but with a TPC, it is possible to well identify the signal induced by solar neutrinos from the Sun by reconstructing the electron recoil initial direction. The angular distribution of these ER will show a peak in the opposite direction of the Sun (produced by neutrinos) over a flat background component.In this talk, with particular focus on the studies on the CYGNO/INITIUM response to low energy electron recoils (ER), as measured on data with the LIME prototype (50 L active volume), we will illustrate the MC simulation of ER sCMOS images, and the comparison between these and real data acquired with the detector exposed to multiple X-ray sources.
We will demonstrate the robust data/MC agreement achieved, and we will furthermore discuss the expected ER angular resolution as evaluated on the MC simulation of LIME data and how this was additionally validated with a smaller prototype data.
We will then discuss how, starting from this realistic detector performances and a GEANT4 simulation of the expected backgrounds for a CYGNO-like 30 m3 detector, we demonstrated how an observation of pp neutrinos is feasible in a reasonable amount of time
Finally, we will illustrate the capability to pose constraints on Non-Standard neutrinos Interactions (NSI), demonstrating how already at a very reduced scale the proposed approach can start to be competitive with Borexino.
Speaker: Samuele Torelli (Donostia International Physics Center) -
156
Testing the Gallium Anomaly Without Using Gallium Detectors
So far, the Gallium Anomaly has been observed only in Ga detectors, which makes it impossible to distinguish between systematic errors due to the detection method (e.g. as an overestimation of the neutrino absorption cross section) and other causes, such as errors in the estimation of the source activity or sterile neutrino.
I will discuss how to test this anomaly using a different detection method, namely electron-neutrino scattering. If the anomaly is still present, we could exclude any explanation related to the Ga detectors; conversely, we would know where its origin lies.
I will present two possible locations for such an experiment: JNE, located in CJPL, and JUNO, the expected signal and the main source of background.Even if the cause of the anomaly is not related to Ga detectors, this kind of experiment can provide us with important information to test other explanations as well. Due to the large dimension of the detector, it would be possible to study the dependence of the anomaly on the baseline, which would be expected if it is due to sterile neutrinos. Moreover, either by looking at the spectral shape or by measuring the scattering angle, it would be possible to test independently the BR of $^{51}$Cr decay, which has been cited as a possible explanation for the anomaly. The requirements for such kind of measurement would be considerably steeper, however.
Speaker: Emilio Ciuffoli (IMP, CAS) -
157
Imaginarity in Neutrino Systems: A Resource-Theoretic Perspective
We present the first analysis of the quantification of imaginarity in neutrino flavor and spin-flavor oscillations by framing neutrino systems as coherent quantum superpositions within the emerging resource theory of imaginarity. Employing measures such as the ℓ1-norm and the relative entropy of imaginarity, we show that imaginarity is nonzero in two-flavor neutrino mixing and peaks when quantum probabilistic features are most pronounced, specifically when survival and transition probabilities approach 1/2. Extending it to the three-flavor framework, we explore the role of a complex CP-violating phase in this quantification. We find that imaginarity, as a resource, can be harnessed not solely from the presence of a complex phase but also from the intrinsic quantum dynamics of flavor mixing. Our findings underscore the fundamental significance of complex numbers in quantum mechanics and position neutrino systems as a rich platform for studying imaginarity through a resource-theoretic lens.
Speaker: Neetu Raj Singh Chundawat (Institute of High Energy Physics, Chinese Academy of Sciences)
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151
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Underground Laboratories: parallel session 4 North Hall #3
North Hall #3
Convener: Xiaolian Wang-
158
Readout Electronics on Waveform Digitization and High-precision Time Measurement
Waveform digitization is the most direct and effective method for capturing comprehensive signal information from particle detectors. This approach enables physicists to extract critical parameters through flexible digital algorithms. In this report, we present our development of waveform digitization electronics utilizing the DRS4 ASIC and a custom-designed Switched Capacitor Array (SCA) ASIC, including circuit design and experimental validation. Furthermore, we address the escalating demand for high-precision timing in particle physics readout systems, where sub-10 ps RMS resolution is now essential. Waveform digitization provides a viable approach to achieve such precision and our detailed implementation of this technique for ultra-high-resolution time measurement is also presented.
Speaker: Jiajun Qin (University of Science and Technology of China) -
159
Development of cryogenic ASICs for HPGe detectors for dark matter and neutrino experiments
Two cryogenic ASICs for HPGe detectors fabricated in 180 nm CMOS process for dark matter and neutrino experiments have been developed. One of them is a wide dynamic range CMOS preamplifier for neutrino-less double beta decay, and the other is a low noise CMOS preamplifier for dark matter detection. The wide dynamic range preamplifier consists of two-stage amplifiers. The first stage is a normal charge sensitive preamplifier and the second stage has dual gain channels to achieve large dynamic range up to 5 MeV. The ENC of high gain stage is simulated to be 4.9 electrons with 0.1 pA leakage current and 2 pF detector capacitance in 77 K, while the ENC of low gain stage is simulated to be 6.2 electrons. The low noise preamplifier is a normal charge sensitive preamplifier optimized for 2 pF detector capacitance. The ENC of the low noise preamplifier is simulated to be 4.5 electrons with 0.1 pA leakage current in 77 K. The chips have been submitted in May and will be received in September. Detailed circuit design and simulation results will be present in the talk.
Speaker: Canwen Liu -
160
Energy and timing resolution boost with waveform analysis
To reconstruct the energy and time of events in the liquid scintillator detector, in a neutrino or dark matter experiment, we need to analyze the waveforms from photomultiplier tubes (PMTs). Fast Stochastic Matching Pursuit (FSMP) samples the posterior of PE time sequence for each waveform. It gains acceleration on GPU, and improves the energy and time resolution of LS detectors. The energy resolution is improved by decreasing $12\%$ of relative resolution.
Speaker: Yuyi Wang -
161
Development of an R-value-Based Trigger Algorithm for Energy Threshold Reduction
Cryogenic detectors are widely employed to investigate rare physical processes such as double beta decay, dark matter interactions, and coherent neutrino scattering. Lowering the energy threshold of detectors not only enhances the understanding of background but also contributes to expanding the scientific scope of experiments.
We have developed a new trigger algorithm based on the Pearson correlation coefficient, commonly referred to as the r-value. This method compares the shape of incoming data waveforms with a predefined signal template to make trigger decisions. Compared to conventional pulse-height-based triggering schemes, the r-value trigger demonstrates superior performance in reducing the energy threshold and improving trigger efficiency. By applying this technique to the AMoRE-I detector and detectors in the AMoRE R&D setups, we achieved significant improvements in lowering the detection energy thresholds. Specifically, we observed that a trigger efficiency above 90% was attained for energies below 20 keV, representing a substantial improvement over the previous threshold range of 50–100 keV.
Speaker: Woo Tae Kim (IBS CUP) -
162
First attempt of reconstruction for multi-point events based on Markov chain Monte Carlo method in liquid scintillator detectors
Liquid scintillator detectors have assumed significant importance in neutrino physics owing to their cost-effectiveness and high precision. Multi\text{-}point reconstruction algorithm can address pileup in the liquid scintillator detectors through simultaneous optimization of temporal and spatial resolution, achieving sub-nanosecond precision in photon arrival time discrimination coupled with sub-centimeter spatial reconstruction accuracy.We develop the Bayesian Probe for Point\text{-}like Events (BAPPE), based on Markov chain Monte Carlo method (MCMC). This method achieves more accurate reconstruction results by jointly considering the energy, position, and timing of the vertex. BAPPE naturally extends to BAPPEn through the generation or annihilation of vertices by the reversible jump MCMC (RJMCMC). BAPPEn can improve particle identification accuracy while substantially refining spatial reconstruction resolution and energy resolution across diverse interaction topologies. Our method has achieved preliminary results in event reconstruction for the Jinping Neutrino Experiment (JNE).
Speaker: 徐 闯 (清华大学工程物理系近代物理研究所) -
163
High-speed and high-precision pulse digitization electronics system with high-bandwidth readout for frontier physics experiments
Modern physics experiments are increasingly characterized by large-scale detection arrays and ever-higher requirements for data-acquisition precision, placing stringent demands on readout electronics. To address these challenges, we present a scalable, high-speed, high-precision waveform-digitization and high-bandwidth readout electronics system. Its multi-channel parallel analog front end supports programmable sampling rates from 125 MS/s to 10 GS/s and achieves intra-chassis channel synchronization better than 500 fs. Optical-fiber interconnection of multiple chassis enables seamless expansion to thousands of channels, while a dedicated 100 Gbps link between each chassis and the host server guarantees low-latency, lossless data transfer under high-throughput conditions. Real-time online processing on an FPGA–GPU heterogeneous platform further accelerates data handling. This robust architecture delivers the data-acquisition and processing performance required by cutting-edge dark-matter, neutrino, and other frontier physics experiments.
Speaker: Haoyan Yang (Tsinghua University)
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158
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Public speechConvener: Bingsong Zou
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164
Unveiling the secrets of the Universe from underground
In recent years, our understanding of the Universe has advanced dramatically. It can be said that the driving force behind this has been the Development of large telescopes. However, as our understanding of the Universe has advanced, it has become clear that telescopes alone cannot reveal all of the mysteries of the Universe. Observations of the Universe from underground have come to play an important role in unraveling the mysteries of the Universe. In this lecture, I will talk about studies of neutrinos and gravitational waves in underground. I will discuss what mysteries of the Universe will be unveiled by these studies.
Speaker: Takaaki Kajita
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164
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On-site registration (start at Saturday 23/08) International Conference Center
International Conference Center
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Plenary session Lufeng Hall
Lufeng Hall
Convener: Yanbei Chen (California Institute of Technology)-
165
The Coming Decade of Gravitational Wave Observation
The LIGO/Virgo/Kagra network of gravitational-wave observatories recently announced the detection of its 200th event during the current observing run (O4). As we approach the 10 year anniversary of the first gravitational wave observation, what is the current state of the international network of detectors, and what does the next decade of gravitational wave observation look like?
Speaker: Dr Jameson Rollins (LIGO Caltech) -
166
Gravitational Waves and the detection at the dawn of time
Almost a decade ago, the first observation of gravitational waves and the discovery of the merger of a binary black-hole system opened up a new window into the Universe. With many more binary-black-hole mergers observed, with in addition the observation and discovery of a binary neutron star merger, the establishment of gravitational wave astronomy revolutionised astroparticle physics. Current gravitational wave observatories are planning system upgrades to maximise their performance to the limits of their facilities.
To further revolutionize gravitational wave astronomy and astrophysics, such as post-merger physics, precision test of GR, and potentially structure formation studies or observe dark matter signatures, new gravitational wave observatories are required. These next generation facilities will extend their reach detecting binary merger events every 5 minutes. With signal to noise ratios of up to 1000 for nearby signals and with detections possible to redshifts of 20, they can observe stellar remnants throughout cosmic time and look deep into the Universe with unprecedented precision.
In this presentation I will walk through the current status of the activities toward the next generation gravitational wave detectors.Speaker: Bram Slagmolen -
167
Space-borne gravitational wave detection in China and progress
China's space-based gravitational wave detection projects will open a new observational window in the mid-to-low frequency band (0.1 mHz to 1 Hz), providing new approaches to understand the origin and evolution of the universe, the formation and evolution of black holes, the nature of gravity, dark energy, and dark matter. Since space-based gravitational wave detection involves a series of key technologies, the TianQin project has proposed a "0-1-2-3" development roadmap, while the Taiji project has put forward a three-step plan. Both TianQin-1 and Taiji-1 were successfully launched in 2019 and have completed their in-orbit tests with outstanding results. Supported by the National Key Program on Gravitational Wave Detection, China has achieved breakthroughs in critical technologies for space-based gravitational wave detection, with the technological levels meeting the requirements for project initiation. In this talk, I will briefly introduce recent progress in China's space-based gravitational wave detection program and provide an outlook on future development.
Speaker: Ziren Luo
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165
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Coffee break International Conference Center
International Conference Center
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Plenary session Lufeng Hall
Lufeng Hall
Convener: Jameson Rollins (LIGO Caltech)-
168
Gravitational experiments in Deep-ground Laboratory
The exceptional experimental conditions of deep-underground laboratories enable ultra-high-sensitivity force and displacement measurements, which are critical for gravitational studies. This talk will discuss potential experiments in facilities like Jinping Lab, including tests of spaceborne gravitational wave detection technologies, characterization of unknown instrumental noise, investigations of gravity-induced decoherence models, and efforts to distinguish quantum gravity from classical gravity. Such experiments could provide unique insights into fundamental physics by leveraging the pristine low-noise environment.
Speaker: Yiqiu Ma -
169
Pulsar timing arrays and implications
In the talk, we will present the results of high precision pulsar timing of 57 millisecond pulsars conducted using the the Chinese FAST 500-meter radio telescope. Particularly, we will highlight the gravitational wave searching efforts of the Chinese Pulsar Timing Array collaboration. More backgrounds and topics on pulsar timing, nanoHertz GW detection, and gravity test will be also covered. Future Chinese perspective in the related field will be also discussed.
Speaker: KeJia Lee (Peking univerisity) -
170
Moon as a Gravitational-Wave Detector
The increasing interest in detecting gravitational waves (GWs) in the decihertz (0.1 Hz) band has inspired the exploration of novel detection methodologies. The Moon, with its substantial mass and low ambient seismic noise, has long been regarded as a promising natural resonant detector for decihertz GWs. Recent proposals for lunar seismology missions—such as China’s Chang’e program and Europe’s Lunar Gravitational-Wave Antenna (LGWA)—require a precise theoretical framework for the Moon’s dynamical response to incident GWs. However, prior analyses have yielded two distinct response functions: one derived from a field-theoretic treatment and the other based on tidal deformation theory, prompting questions regarding their physical equivalence.
In this talk, I will present a unified analytical and numerical treatment of the Moon’s normal modes under GW excitation. I will demonstrate that the two response functions are fundamentally identical, with apparent discrepancies arising solely from gauge-dependent coordinate choices. Employing the correct formulation, we reassess the sensitivity of proposed lunar seismometer arrays, revealing a flatter response spectrum in the 0.001–0.1 Hz band compared to earlier predictions. Based on such response functions, I will discuss the detectability of a stochastic GW background using lunar seismic networks, deriving updated angular response (pattern) functions and overlap reduction functions while relaxing previous idealizations in instrument modeling.
To address the challenges posed by the Moon’s structural inhomogeneity, I will show results from our 2D spectral-element-method (SEM) simulation, benchmarking its accuracy against semi-analytical solutions and systematically evaluating its limitations. These findings have provided a consolidated theoretical foundation for lunar GW response modeling, refined scientific targets for future lunar GW observations, and laid down critical design constraints for next-generation lunar GW detectors.
Speaker: Xian Chen (Peking University)
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168
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Lunch Yu’ou Building
Yu’ou Building
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Dark Matter and Its Detection: parallel session 5A Conference Room F2-R1
Conference Room F2-R1
Convener: Yi Wang (IHEP, CAS)-
171
Searches for Light Dark Matter with DarkSide-20k and DarkSide-LowMass
Liquid argon, with its relatively light atomic mass and low energy
threshold in the ionisation channel, has proven to be a promising
target medium for the direct detection of dark matter candidates with
masses below 10 GeV/c².The Global Argon Dark Matter Collaboration (GADMC) is currently
constructing the DarkSide-20k detector, which is primarily focused on
high mass WIMP detection. We propose a new detector, DarkSide-LowMass,
building on the experience from DarkSide-50 and the ongoing
development of DarkSide-20k. DarkSide-LowMass is specifically
optimised for low-threshold, electron-counting measurements, and its
sensitivity to light dark matter is explored under various energy
thresholds and background conditions.In this talk, I will present the latest developments in the search for
low-mass dark matter using the proposed DarkSide-LowMass detector,
along with recent sensitivity studies for light dark matter detection
with DarkSide-20k.Speaker: Masayuki Wada (Astrocent, CAMK PAN) -
172
BULLKID-DM: searching for light WIMP with monolithic arrays of detectors
BULLKID-DM is a novel experiment designed for the direct searches of particle dark matter candidates with mass around 1 GeV, or below, and cross-section with nucleons smaller than $10^{-41}$ cm$^2$.
The detector consists of a stack of diced silicon wafers, acting as arrays of particle absorbers, sensed by multiplexed Kinetic Inductance Detectors (KIDs). The target will amount to 800 g subdivided in more than 2000 silicon dice. The aim is to control the background from natural radioactivity by creating a fully active structure and by applying fiducialization techniques. Encouraging results have been reached by the first 20 g prototype of the detector, built with 60 cubic voxels (of dimensions 5.4 x 5.4 x 5 mm$^3$) that are carved out of a single 5 mm thick 3'' silicon wafer.
Here we present the first operation of the 3-wafer demonstrator array (for a total of 60 g and 180 silicon dice), operated on surface with a passive lead shield in order to reduce the background level below $10^5$ d.r.u. We also discuss about the energy calibration, the analysis procedure and the comparison with the simulation conducted by the collaboration.
Finally, we present the plan for the deployment of the experiment at the shielded underground site of Gran Sasso laboratories in Italy. The commissioning will happen in two stages: first, the demonstrator array will be deployed at the beginning of 2026 in the cryo-platform. Once the success of the demonstrator stage is ensured and the setup is fully characterized, the full experimental setup will follow and it is expected to be commissioned at Gran Sasso at the beginning of 2027.Speaker: Matteo Folcarelli (Sapienza University of Rome) -
173
DAREDEVIL
The DAREDEVIL (DARk-mattEr-DEVIces-for-Low-energy-detection) is a new project aiming to develop a novel class of detectors to study Dark Matter candidates with mass below 1 GeV/c². The detection channel is DM-electron scattering, where the excitation energies of the electrons should be matched to the transferred momenta. The only materials with energy gaps of eV or below are special semiconductors, Dirac Semimetals, Weyl Semimetals, and Scintillators. Such materials, already explored from a theoretical point of view, will be implemented in a detector as planned by the DAREDEVIL project. The first phase of the project aims at designing a novel class of gram-scale detectors with meV threshold suitable for light DM-electron scattering detection. In order to achieve the high performances needed for detecting such small energy depositions, we will use these crystals as absorbers in low-temperature calorimeters with dual phonon and IR-photon readout. In this contribution, we present the very first results of a low-temperature calorimeter based on GaAs as the target crystal, operated at 15 mK, coupled to a Neutron Transmutation Doped thermistor for the phonon readout. Furthermore, we have conducted the first tests of the double readout technique with a germanium light detector utilizing the Luke effect, and in the future, we aim to test CdTeHg-based photon detector tuned to detect its IR scintillation light.
Speaker: andrea Melchiorre (LNGS) -
174
Search for Dark Sector Particles at a Nuclear Reactor from the NEON Experiment
The NEON experiment, located 23.7 meters from the Hanbit nuclear reactor core in Korea, offers a powerful platform to explore dark sector particles using the intense MeV-scale photon flux from a commercial reactor. In this talk, we present results from searches for axion-like particles (ALPs) and light dark matter (LDM) using 1.2 years of data collected with six NaI(Tl) scintillation detectors. The ALP analysis probes the cosmologically motivated “triangle” region in parameter space for the first time using a reactor-based experiment, setting new limits on ALP-photon and ALP-electron couplings in the MeV mass range. In parallel, our LDM search investigates dark photon-mediated LDM production in the reactor core and subsequent scattering off electrons in the detector, extending experimental sensitivity down to dark matter masses of 1 keV and providing the first laboratory-based constraints below 100 keV. These results highlight the unique potential of reactor experiments to probe light dark sector particles in previously inaccessible regions, offering a complementary approach to astrophysical and accelerator-based searches.
Speaker: Hyunsu Lee (Institute for Basic Science)
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171
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Dark Matter and Its Detection: parallel session 5B Conference Room F2-R2
Conference Room F2-R2
Convener: Xiaojun Bi-
175
IceCube’s Sensitivity Prospects to MeV-Scale Axion-Like Particles from Core-Collapse Supernovae
We present a novel framework to estimate the sensitivity and discovery potential of IceCube to axion-like particles (ALPs) produced in core-collapse supernovae (CCSNe), covering ALP masses from 1 MeV to several hundred MeV. A key feature of this work is the explicit handling of the final-state leptons produced in ALP interactions with 16O nuclei and protons, which can generate Cherenkov light detectable in IceCube. These processes are being fully integrated into a detector-level simulation chain, enabling realistic detector signal modeling beyond existing estimates. The framework enables projections for both direct detection sensitivities and constraints based on time delays relative to the neutrino burst, across a range of ALP emission models. This approach may also extend to other MeV-scale dark sector particles. Preliminary sensitivity estimates are in progress and will be presented.
Speaker: Nora Valtonen-Mattila (Ruhr Universität Bochum) -
176
Search for Dark Matter spectral lines around the Galactic Centre with CTAO LST-1
Dark Matter (DM) remains one of the most profound mysteries in modern physics. Among the many proposed candidates, Weakly Interacting Massive Particles (WIMPs) stand out due to their strong theoretical motivation and testable implications. A definitive detection of monoenergetic gamma-ray lines from WIMP annihilation would provide a direct probe of electroweak-scale interactions, offering a complementary approach to collider and direct detection experiments.
At very high energies (VHE), WIMP annihilation is expected to yield gamma rays alongside other Standard Model particles. The Galactic Center (GC), owing to its proximity and high expected DM density, is a prime target for such searches. Imaging Atmospheric Cherenkov Telescopes (IACTs) have set stringent limits on DM properties in the GC region, with the MAGIC telescopes providing the strongest constraints in the 20–100 TeV range through Large Zenith Angle (LZA) observations. However, the limited field of view (FoV) of MAGIC (<3.5°) has restricted detailed studies of the broader GC environment, where DM density enhancements are anticipated.
The first Large-Sized Telescope (LST-1) of the Cherenkov Telescope Array Observatory (CTAO), located at the Roque de Los Muchachos Observatory in La Palma, Spain—near the MAGIC site—has been observing the GC since 2021. With its wider FoV of 4.5°, LST-1 offers new opportunities for extended searches. Although the GC transits at low elevation, necessitating LZA observations (ZA > 58°), such conditions enhance sensitivity to gamma rays up to and beyond 100 TeV.
In this work, we present the first WIMP gamma-ray line search with LST-1. We detail the characterization of LST-1’s instrument response functions under LZA conditions, along with a comprehensive background rejection strategy for monoscopic observations. Using advanced statistical methods and spectral line search techniques applied to simulated data, we demonstrate significant improvements in sensitivity and methodology. These results highlight LST-1’s growing potential in the indirect search for DM at the GC.
Speaker: Tomohiro Inada (Kyushu University) -
177
Understanding the Origin of Cosmic-Ray Electrons and Positrons
The electron and positron fluxes measured by the Alpha Magnetic Spectrometer (AMS) exhibited complex energy dependencies. In the entire energy range the positron flux is well described by the sum of a power-law term associated with the positrons produced in the collision of cosmic rays, which dominates at low energies, and a new source term of positrons, which dominates at high energies. This new source has a finite energy cutoff, which is established with a significance of ~5σ. These experimental data on cosmic ray positrons show that, at high energies, they predominantly originate either from dark matter annihilation or from a new astrophysical source.
In the entire energy range the electron and positron spectra have distinctly different magnitudes and energy dependences. At high energies, AMS data show that the electron spectrum can be best described by the sum of two power law components and a positron source term. This is the first indication of the existence of identical charge symmetric source term both in the positron and in the electron spectra and, as a consequence, the existence of new physics.
Speaker: Shanglin Li (中国科学院高能物理研究所) -
178
Search for Cosmic-Ray Antinuclei from Dark Matter with the GAPS Antarctic Balloon Mission
The General Antiparticle Spectrometer (GAPS) is a balloon-borne experiment, firstly optimized to identify low-energy (≲ 0.25 GeV/n) cosmic antinuclei from dark matter annihilation or decay. With a novel detection approach that uses the uniquely characterized atomic X-rays and charged particles from the decay of exotic atoms, the GAPS program will deliver an unprecedented sensitivity to low-energy cosmic antideuterons, an essentially background-free signature of dark matter. In addition, GAPS will deliver a precise antiproton spectrum with high statistics in an unexplored energy range as well as a high sensitivity to cosmic antihelium.
The GAPS detector instrument consists of a tracker of >1000 custom lithium-drifted silicon detectors, which is cooled by a novel oscillating heat pipe thermal system, and a precision-timing, large-area time-of-flight system. The GAPS project has completed the on-ground commissioning in Antarctica and anticipates its first of three Antarctic flights in late 2025. This talk will cover the overview of the GAPS mission while highlighting results from the Antarctic ground-testing campaign.
Speaker: Prof. Mengjiao Xiao (Shanghai Jiao Tong University)
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175
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Gravitational Waves: parallel session 5 Conference Room F1-R3
Conference Room F1-R3
Convener: Alba Romero-Rodriguez (Laboratoire D'Annecy de Physique de Particules (LAPP))-
179
Gravitational wave emission from merging strange quark star - strange planet.
Strange-quark matter (SQM) may be the true ground state of hadronic matter, indicating that the observed pulsars may actually be strange stars (SSs), but not neutron stars. According to the SQM hypothesis, the existence of a hydrostatically stable sequence of SQM stars has been predicted, ranging from 1 to 2 solar mass SSs, to smaller strange dwarfs and even strange planets. While gravitational wave (GW) astronomy is expected to open a new window to the universe, it will shed light on the search for SQM stars. Here we show that due to their extreme compactness, strange planets can spiral very close to their host SSs without being tidally disrupted. Like inspiraling neutron stars or black holes, these systems would serve as new sources of GW bursts, producing strong GWs at the final stage. The events occurring in our local universe can be detected by upcoming GW detectors, such as Advanced LIGO and the Einstein Telescope. This effect provides a unique probe to SQM objects and is hopefully a powerful tool for testing the SQM hypothesis.
Speaker: 永锋 黄 (南京大学) -
180
Multiband Gravitational Wave and Multimessenger Astronomy with Galactic compact binaries
The upcoming era of gravitational wave (GW) astronomy heralds unprecedented opportunities to study compact binaries, in particular double neutron stars (DNS), double white dwarfs (DWD), and binary black holes, through their gravitational waves, providing important insights into binary evolution, NS physics, and the overarching architecture of the universe. In this talk, I will give an overview of our investigation on the scientific objectives and data analysis pertinent to these compact binaries, emphasizing the multi-messenger observations of DNSs and DWDs in our Galaxy that synergize the capabilities of LISA, TianQin, and current and future optical and radio telescopes, and the promising multi-wavelength observations of the low-frequency GWs due to the binary motion of a DNS and the high-frequency GWs due to the spin of the aspherical NS component. The talk also discusses the challenge of data analysis for the stellar-mass binary black holes and presents our novel solution, which includes both algorithmic and hardware accelerations.
Speaker: Yan Wang (Huazhong University of Science and Technology) -
181
Long-term multi-messenger signal simulation of a supernova
Supernovae are very promising multi-messenger astronomical targets. They emit electron-magnetic waves, neutrinos, gravitatinal waves and maybe beyond-standard model particles like axions.
Neutrinos are deeply involved in the mechanism of supernova explosions, which have been investigated along with the development of neutrino radiation transport. Gravitational waves are emitted from drasticaly moving matter. For further clarification, it is essential to observe neutrinos and gravitational waves directly exiting the high-density core. The extreme environment of the core may produce axions. Most recent simulations of supernova neutrinos have been of the order of 1 second due to their high computational cost. However, from the only observed case of supernova neutrinos, SN 1987A, it is predicted that if a supernova explosion occurs in the Galaxy, the neutrino detector, Super-Kamiokande, will observe more than several thousand neutrinos for more than 10 seconds. For this reason, we have performed long time calculations using neutrino radiation transport calculations with and without axions. Moreover I estimated long-term gravitational waves with the asteroseismology. In this talk, I will present the results of neutrino, gravitational waves and axions up to 20 seconds. I will also give a discussion on posibility for axion to be detected from galactic supernovae.Speaker: Masamitsu Mori (Numazu College of technology) -
182
Gravitational Waves with Complex Features as Precision Probes of Cosmology
Gravitational waves can exhibit complex features in various scenarios, such as orbital eccentricity, gravitational lensing, and the presence of higher-order modes. These effects are especially relevant for next-generation gravitational wave detectors, which will have the sensitivity to capture such rich signal structures. In this talk, I will present our recent work on leveraging these complex gravitational wave signals as precision probes of cosmology—such as measuring the Hubble constant—and as tools to test fundamental theories of gravity.
Speaker: Tao Yang (Wuhan University) -
183
Detecting Gravitational Waves from Exoplanets Orbiting Binary Neutron Stars with B-DECIGO and DECIGO
The first detection of a gravitational-wave (GW) signal in 2015 have opened a new observational window to probe the universe. This probe can not only reveal previously inaccessible binaries, black holes, and other compact objects, but also can detect exoplanets through their imprint on GW signals, thereby significantly extend current exoplanet surveys. To date, nearly 6 000 exoplanets have been confirmed, yet most reside either in the solar neighbourhood or along the sightline toward the Galactic bulge, reflecting the range limits of existing electromagnetic techniques. We follow the previous work N. Tamanini & C. Danielski (2019) and demonstrate that frequency modulations in GW signals from early-stage binary neutron stars (BNSs) induced by circumbinary exoplanets (CBPs), can be measured by future space-borne detectors such as Laser Interferometer Space Antenna (LISA) and DECi-hertz Interferometer Gravitational wave Observatory (DECIGO). For an equal-mass BNS system of 1.4 $M_{\odot}$ + 1.4 $M_{\odot}$, DECIGO could detect such planets out to distances of ~ 10 Mpc, offering an unprecedented opportunity to study planetary formation and evolution.
Speaker: Wenlong Guo (Beijing Normal University)
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179
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High-Energy Astrophysics and Cosmic Rays: parallel session 5 Conference Room F1-R2
Conference Room F1-R2
Convener: Zhe Li-
184
Temporal Structures in Electron and Positron Spectra and Charge Sign Effects in Galactic Cosmic Rays
We present the precision measurements of daily cosmic electron fluxes in the rigidity range from 1.00 to 41.9 GV with 13.5 years data collected with the Alpha Magnetic Spectrometer (AMS) aboard the International Space Station from May 2011 to November 2024. The electron fluxes exhibit variations on multiple time scales. Recurrent electron flux variations with periods of 27 days, 13.5 days, and 9 days are observed. We found that the electron fluxes show distinctly different time variations from the proton fluxes. Remarkably, complex hysteresis between the electron flux and the proton flux is observed. Furthermore, significant structures in the electron-proton hysteresis are observed corresponding to sharp structures in both fluxes.
The positron fluxes show distinctly different time variations from the electron fluxes at short and long time scales. A hysteresis between the electron flux and the positron flux is observed. Unexpectedly, on the long-term time scale positron fluxes are modulated more than proton fluxes.
Speaker: Zetong Sun -
185
Antiprotons and Elementary Particles over a Solar Cycle: Results from the Alpha Magnetic Spectrometer
We present results over an 11-year Solar cycle of cosmic antiprotons in the rigidity range from 1.00 to 41.9 GV. The antiproton fluxes exhibit distinct properties. Compared with other cosmic elementary particle fluxes (proton, electron, and positron), the magnitude of the antiproton flux temporal variation is significantly smaller. A hysteresis between the antiproton fluxes and the proton fluxes is observed, whereas the antiproton and electron fluxes show a linear correlation. With a model-independent analysis, we found a universal relation between the shape of the rigidity spectrum and the magnitude of flux temporal variation over an 11-year Solar cycle for both positively and negatively charged particles. The simultaneous results on antiproton, proton, electron and positron provide unique information for understanding particle transport in the Solar System as a function of mass, charge, and spectral shape.
Speaker: Senquan Lu (IHEP, CAS) -
186
The Remarkable Influence of Corona Field on Solar Gamma Ray
The Sun shines bright as a gamma ray source, caused by hadronic galactic cosmic ray interactions in the photosphere and chromosphere. Fermi-LAT and HAWC have observed these so-called solar disk gamma rays in GeV to TeV energy range, and discovered many oddities, including high flux, anti-correlation to solar activity cycle, and time dependent morphology.
Solar magnetic field plays a key role in affecting the gamma ray emission. The field in corona, the Sun's outer atmosphere, can change the isotropy of galactic cosmic ray. In the inner atmosphere, the field can increase the yield of escaped gamma ray per cosmic ray interaction. However, due to the complexity of the Solar magnetic field, simple analytical calculations have been insufficient and the exact mechanism that connects solar cycle to gamma ray flux is uncertain.
Here we report the result of our simulation, G4SOLAR2, on CR interaction with Sun atmosphere and magnetic field. We investigate a couple of well tested corona field models: PFSS and MHD, for a variety of time periods during solar cycle.
Our simulation shows that corona field is the major component that affects GeV gamma ray. Specifically, the area of open corona field is directly correlated with $<10$ GeV gamma ray flux, and the changes throughout solar cycle explains the time variation in gamma ray flux. Further more, gamma ray telescopes with enough angular resolution can verify the validity of solar corona field models.Speaker: Chingam Fong (The Chinese University of Hong Kong) -
187
Expectation of measuement of Iron Spectrum at Knee region
For over decades, the structure of the cosmic ray all-particle spectrum has been progressively refined through different observations. The fine structure of the spectrum carries important information about the acceleration and propagation of cosmic rays, yet the causes of these fine structures have not been fully elucidated.
For the cause of the most prominent “knee" region, there are two different point of view. In the context of astrophysics, both scenarios acceleration and propagation hypotheses entail that the cut–off energy for each individual element depends on its charge Z. From a particle-physics perspective, the observed knee in the spectrum of extensive air showers is connected with the changes of inelastic collisions of the primary protons near the upper boundary of atmosphere. Such effects lead to a nuclear mass-dependent cut–off. By conducting a comprehensive and precise measurement of the knee region with iron nuclei, and comparing the knee region position in the proton spectrum, can we provide decisive evidence in the choice between the two interpretations.
This report utilizes simulation data to investigate the capability of LHAASO to measure the iron nucleus energy spectrum.Speaker: 小溪 周 (IHEP) -
188
Constraint on Lorentz invariance violation: combined limit from a cooperation of Imaging Atmospheric Cherenkov Telescopes
Lorentz invariance violation (LIV) arises from modifications to the dispersion relation of massless particles in effective models attempting to coherently merge quantum field theories and general relativity. One way of detecting or constraining LIV effects is by measuring time delays in the arrival of high-energy photons from astrophysical sources. Suitable targets are variable, distant and highly energetic objects such as pulsars, gamma-ray bursts (GRBs), and active galactic nuclei (AGN) flares. However, a major challenge arises from intrinsic time lags due to source-specific emission processes. To improve the precision of these measurements and distinguish potential LIV-induced delays from intrinsic effects, a collaborative effort has been established among major Imaging Atmospheric Cherenkov Telescopes (IACTs): H.E.S.S., MAGIC, VERITAS, and the first Large-Sized Telescope (LST-1) of CTAO. The Gamma-ray LIV Working Group (γLIV WG) aims to combine observational data from multiple sources, enhancing the sensitivity and robustness of LIV searches. We present the first set of limits on the LIV energy scale derived from a combination of real data from IACT experiments.
Speaker: Ugo Pensec (LPNHE - CNRS)
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184
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Neutrino Physics and Astrophysics: parallel session 5A North Hall #1
North Hall #1
Convener: Carsten Krauss-
189
First observation of reactor antineutrinos by coherent scattering with CONUS+
The talk will cover results of the CONUS+ experiment which led to the first observation of Coherent Elastic neutrino-nucleus Scattering (CEvNS) with reactor antineutrinos. The current status, a near term outlook, the physics implications and perspectives will also be discussed.
Speaker: Manfred Lindner (Max Planck Institute for Nuclear Physics) -
190
Experiment nuGeN at Kalinin NPP. Status and latest results.
The $\nu$GeN experiment is aimed at studying rare processes from antineutrino scattering on germanium. It is located in the close vicinity of the reactor core of the Kalinin Nuclear Power Plant (KNPP) at Udomlya, Russia. The experimental setup is installed under reactor unit #3 of KNPP on the moving platform, which allows changing the distance from the center of the 3.1 GW$_{th}$ core from 11.1 to 12.2 m. In this way, we obtain an enormous antineutrino flux of (3.6-4.4)x10$^{13}$ $\nu$/cm$^2$/s. Materials of the reactor surrounding provide about 50 m w.e. overburden, which serves as a good shielding against cosmic radiation. In combination with a low ambient background, it gives us a unique opportunity to investigate antineutrino properties at the best experimental location in the world. To detect signals from the neutrino scattering, we use a high-purity, low-threshold germanium detector surrounded by passive and active shielding. A specially developed acquisition system allows suppressing events that correspond to noise. The current status of the experimental setup, data taking, and new results will be presented.
Speaker: Alexey Lubashevskiy (Joint Institute for Nuclear Research) -
191
New Limits on Neutrino-Nucleus Elastic Scattering at Kuo- Sheng Nuclear Reactor
Nuclear reactors are source of intense low energy neutrinos providing a great tool to look for neutrino-nucleus elastic scattering in the fully coherent regime. Taiwan EXperiment On NeutrinO (TEXONO) is few decades old research program [1] at Kuo-Sheng nuclear power plant working with state-of-art high purity point-contact Germanium detectors with O(100 eV) threshold [2]. In this work we will present our latest findings exploiting the Reactor ON(OFF) data with exposure of 242(357) kg.days. For this data set 4.7 times excess over the SM predicted cross section is excluded at 90% C.L. considering the standard Linhard parameterization k = 0.162 [3] with achieved 200 eV ionization threshold. Further, the updated analysis with additional 250(440) kg.days exposure, and future goals will also be presented.
Reference:
1. H. T. Wong et al. (TEXONO Collaboration), Research program towards observation of neutrino-nucleus coherent scattering, J. Phys. Conf. Ser. 39, 266 (2006).
2. A. Soma et al. (TEXONO Collaboration), Characterization and performance of germanium detectors with sub-keV sensitivities for neutrino and dark matter experiments, Nucl. Instrum. Methods Phys.Res., Sect. A 836, 67 (2016).
3. S. Karmakar et al. (TEXONO Collaboration), New Limits on the Coherent Neutrino-Nucleus Elastic Scattering Cross Section at the Kuo-Sheng Reactor-Neutrino Laboratory, Phys. Rev. Lett. 134, 121802 (2025).Speaker: Dr Manoj Kumar Singh (Institute of Physics, Academia Sinica, Taipei, 115201, Taiwan) -
192
Status and recent results from the CONNIE experiment with Skipper-CCDs
The Coherent Neutrino-Nucleus Interaction Experiment (CONNIE) uses the silicon (Si) in thick fully depleted charge-coupled devices (CCDs) as target to search for the coherent elastic scattering of reactor antineutrinos off nuclei (CEvNS) and search for new physics. Located at 30 m from the core of the Angra 2 nuclear reactor in Rio de Janeiro, Brazil, CONNIE has run on the site since 2016 undergoing various upgrades. In 2021 two sub-electron readout noise Skipper-CCDs (total Si mass of 0.5 g) were installed and new techniques were developed allowing the experiment to reach an energy threshold of 15 eV. Data collected in 2021 and 2022 with a 14.9 (3.5) g-day exposure with reactor-on (off) were used to obtain an upper limit on CEvNS rate comparable with those of the standard CCD runs with higher exposures. Improved limits on models with light mediators have been obtained, as well as the best limits on DM-electron scattering from a surface experiment. In addition, world-leading limits on the charge of millicharged particles with masses in the range from 1 eV to 10 MeV have been imposed frum a comprehensive analysis and the combination of data from another Skipper-CCD experiment at the Atucha II reactor in Argentina. In 2024 a new Multi-Chip Module (MCM) with 16 Skipper-CCDs with the Oscura experiment design was installed, increasing the Si mass to 8g. In this talk we present the status and latest results from the experiment, the progress on the commissioning of the MCM and comment on the future prospects for detecting CEvNS with Skipper-CCDs.
Speaker: Alexis Armando Aguilar-Arevalo (Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México) -
193
New results from the commissioning of the NUCLEUS experiment at the Technical University of Munich
The NUCLEUS experiment aims to perform precision measurements of coherent elastic neutrino-nucleus scattering (CEvNS) of reactor antineutrinos in the fully coherent regime. In the first phase, CaWO$_4$ cryogenic detectors will be used as targets and the experimental apparatus will be installed at the Chooz nuclear power plant in France, in the vicinity of two 4.5 GW$_{th}$ reactor cores. The target detectors will be integrated into a compact veto system, incorporating both active and passive shielding, designed to achieve a CEνNS signal-to-background ratio of approximately 1 in the energy region of interest (20 - 100 eV) .
In this talk, we present new results from the commissioning of a substantial version of the experiment at the shallow Underground Laboratory of the Technical University of Munich. Additionally, we discuss progress on upgrades to the detector systems and provide a status update of the relocation of the experimental apparatus to the reactor site, in preparation for a technical run at Chooz scheduled for 2026.Speaker: Elisabetta Bossio (CEA Paris Saclay)
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189
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Neutrino Physics and Astrophysics: parallel session 5B North Hall #2
North Hall #2
Convener: Mauricio Bustamante (Niels Bohr Institute, University of Copenhagen)-
194
Prospects for detecting fast-time features in the neutrino lightcurve of nearby supernovae in neutrino telescopes
Core-collapse supernovae are among the most energetic processes in our Universe and play a crucial role for the chemical composition of the Universe. Neutrinos, produced in vast numbers during the collapse, offer a direct probe into the hydrodynamics and energy transport processes within a supernova. Fast-time variations in the neutrino luminosity and mean energy could carry information about phenomena like turbulence, convection, and shock revival.
In this talk, we examine the capabilities of large-volume neutrino telescopes such as the IceCube Neutrino Observatory and the planned IceCube-Gen2 detector in identifying fast-time features in the neutrino light curve.
Speaker: Jakob Beise (Uppsala University) -
195
Towards imaging Earth’s large-scale structures by directional geoneutrino detection with Ocean Bottom Detector
Geoneutrinos are electron antineutrinos produced by beta decays of radioactive isotopes within Earth. Their detection provides a unique opportunity to quantify the production of radiogenic heat and its distribution in the planet. Despite their significance, geoneutrinos are challenging to detect due to their weak interactions with matter, which necessitates highly sensitive and specialized detection techniques.
Nevertheness, in 2005, the KamLAND experiment (Japan) became the first to successfully detect geoneutrinos, providing groundbreaking insight into Earth's power. The achievement spurred the development of new methods for studying Earth's structure, bridging neutrino physics with geochemistry and geophysics. The Borexino experiment (Italy) later confirmed the detection of geoneutrino, and ongoing projects such as SNO+ (Canada) and the upcoming JUNO experiment (China) aim to further our understanding of Earth's interior through continued geoneutrino detections.
The detectors mentioned above, however, are all located in thick continental crusts that have a high concentration of radioactive isotopes, which limits our ability to investigate deeper layers of Earth. To address this challenge, a project called Hanohano was proposed in 2005. However, due to various challenges, it was never realized. Building on past efforts, a project called Ocean Bottom Detector (OBD) was proposed in 2019 by Research Center for Neutrino Science, Tohoku University, based on the extensive operational and technical experience gained from KamLAND. It involves placing a liquid scintillator neutrino detector on the ocean floor off the coast of Hawaii, where the oceanic crust is thin and contains fewer radioactive isotopes. This makes the location ideal for directly detecting geoneutrinos from the mantle. To launch this international collaboration, the project is being pursued in active cooperation with institutions such as the University of Hawai’i, Lawrence Livermore National Laboratory (LLNL), and Japan Agency for Marine-Earth Science and Technology (JAMSTEC).
Another key challenge is that traditional detection methods lack the angular resolution needed to determine the direction of incoming antineutrinos, making it difficult to confirm whether a detected signal truly originates from Earth's interior. In recent years, several new techniques have been proposed and developed to enable antineutrino detectors to achieve angular resolution. These include gadolinium-doped liquid scintillators, which improve neutron tagging, and segmented detector designs that allow for more precise reconstruction of the interaction vertex.
In this presentation, we explore potential observational results that could be obtained if the OBD is equipped with angular resolution. Such observations could not only provide direct evidence of the directionality of geoneutrinos, but also offer valuable insights into the structure and dynamics of Earth's deep interior, particularly the large low-shear-velocity provinces (LLSVPs). These structures located at the base of the mantle have attracted increasing attention in geoscience because of their important role in mantle convection, plume generation, and thermal evolution of the earth.
V. A. Li’s contribution to this work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-2005421.
Speaker: Zhihao Xu (Tohoku University) -
196
Dissecting the diffuse supernova neutrino background flux over wide energy range in upcoming era
The diffuse supernova neutrino background (DSNB), formed by neutrinos released from stellar core collapse over the cosmic history and floating in the Universe, is believed a key probe for stellar astrophysics as well as cosmic chemical evolution picture. Its experimental confirmation is still awaited, yet a recent search at the Super-Kamiokande water Cherenkov detector reports an exclusion of zero DSNB at a significance over 2$\sigma$, possibly implying the first hint. In the upcoming decade, larger underground detectors will operate, among which Hyper-Kamiokande, the successor of Super-Kamiokande with a $\sim$8 times larger volume, and JUNO, a $\sim$20 kton liquid scintillation detector in China, are quite promising for DSNB studies. Combining the data from these next-generation detectors will surely contribute to dissecting the DSNB flux shape over the wide energy range which is reflection of many astrophysical factors. Toward this purpose, we are developing the DSNB analysis framework, CARNE (Code for Analyzing Relic NEutrinos), with considering realistic background estimate and its systematic uncertainties at different types of neutrino detectors. In this presentation, we will report the basic idea and development status of this framework and show the expected sensitivity to models at future detectors.
Speaker: Yosuke Ashida (Tohoku University) -
197
The TeV astrophysics of the Sun
Surprisingly, the Sun is found that be a bright gamma-ray source at TeV, due to cosmic rays interacting with the solar atmopshere and produces hadronic gamma rays. I will discuss the detection of TeV solar gamma rays by HAWC, which could be a novel probe for solar magnetism, and its implications for detecting TeV neutrinos and dark matter searches from the Sun.
Speaker: Prof. Kenny Chun Yu Ng (The Chinese University of Hong Kong) -
198
Power reactor monitoring with antineutrinos by the DANSS detector
DANSS detects antineutrinos from a 3.1 GW$_{th}$ power reactor of Kalininskaya NPP for almost 9 years. The data sample is about 10 million events and features excellent signal to background ratio in excess of 50. Along with the leading results in the sterile neutrino searches, DANSS demonstrates various opportunities of antineutrino application for practical purposes of reactor monitoring. The talk will present the observation of the reactor power with the relative systematic uncertainty about 0.8%, as well as the reconstruction of the fission fractions in the reactor core with the accuracy, comparable to that from the fuel evolution calculations. A simple but effective approach to determine the antineutrino yield ratio from $^{235}$U and $^{239}$Pu fuel isotopes will be discussed. The analysis of the data from more than 5 full fuel campaigns makes possible the decomposition of the neutrino spectra from the two major burning isotopes. The DANSS detector reliably proofs the possibility to use antineutrinos as a totally independent way of the monitoring of the reactor core parameters with accuracies, comparable or even better than that from the conventional methods.
Speaker: Dmitry Svirida (NRC KI)
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194
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Underground Laboratories: parallel session 5 North Hall #3
North Hall #3
Convener: Long Ma (Fudan University)-
199
Validation of LMO crystals for the CUPID Experiment
CUPID (CUORE Upgrade with Particle IDentification) will search for the neutrinoless double-beta decay of Mo-100 using an array of 1596 Li$_2$MoO$_4$ (LMO) crystals enriched at 95\% in $^{100}$Mo operated as cryogenic calorimeters. The scintillation light produced by the LMO crystals will enable active, event-by-event particle identification, which is crucial to achieve the target background level of $10^{-4}$ counts/keV/kg/year at the Q-value of the transition (3034 keV). The CUPID LMO crystals must meet a series of strict requirements regarding both radiopurity and calorimetric performance (light yield and energy resolution). To assess the quality, a fraction of the produced crystals will undergo dedicated measurements at cryogenic temperatures. This program, known as the CUPID Crystal Validation Runs (CCVRs), has already begun with dedicated measurements at $\sim$ 15 mK carried out on the pre-production batches in a low-background dilution cryostat at the Laboratori Nazionali del Gran Sasso (LNGS) in Italy, the same underground laboratory that will host CUPID. The CCVR validation program will continue throughout the production of the CUPID crystals. In this talk, I will present the CCVR protocol, outlining the detector assembly, the data analysis methodology, and the first results obtained from the preliminary batches of crystals produced during the pre-production phase.
Speaker: Massimo Girola (INFN - MIB) -
200
High Spectral Resolution Perovskite Semiconductor CsPbBr3 for Gamma-ray Detection
Halide perovskite semiconductors for direct X- and gamma-ray detection have currently attracted enormous attentions due to the bright prospects in various scenarios, such as medical imaging and nuclear nonproliferation in homeland security and high energy physics. Halide perovskites featuring excellent charge transport properties, low cost in preparation, and versatile processing method may offer a competitive opportunity compared to the conventional room-temperature semiconductors. As previously evidenced, the hole carriers in perovskite semiconductors have superior transport properties than electrons carriers. The unipolar sensing strategy could eliminate the such challenge induced by the electron trapping issue. However, the development of unipolar detectors for perovskite semiconductors is still at an early stage where substantial efforts are requested upon the device optimization. Here, our progresses on the perovskite CsPbBr3 detectors were reported with the configuration of pixelated and virtual Frisch grid type aiming at their deployment for the high energy resolution gamma-ray spectroscopy, ~1%@662 keV. The thickness of single-crystal detectors varied from ~3 to 20 mm which were grown by melt method. The unipolar design as indicated adequately restrained signal induction region of the hole carrier, which in turn eliminated the depth of interaction dependency between the signal amplitude partially. The carrier transport and collection dynamic was simulated in consideration of the radiation-matter interaction, charge transport and signal induction. The relationship of the carrier drift time and the signal amplitude in various detector configuration were analyzed to estimate the charge transport properties of hole carrier. The energy resolution was determined based on the signal amplitude analysis. The issues in achieving high energy resolution by unipolar perovskite semiconductors were also analyzed. Furthermore, we also demonstrated that balances charge transport for both electron and hole carriers can also be achievable through zone refining processing facilitating impurity segregation to achieve a high purity level of ~6N. Notably, a champion energy resolution of 1.3% with an outstanding photopeak-to-Compton ratio of ~5.3 was attained in an ambipolar planar detector. Such improved strategy also enables the superior reproducibility and uniformity for spectroscopic-grade CsPbBr3 crystals. We anticipate that this work shall expedite scalable manufacturing and practical applications of CsPbBr3 detectors.
Speaker: Yihui He (Soochow University) -
201
The Study of Tungsten Thin Films for Ultra-low Tc Superconducting Transition Edge Sensors for 0vββ Experiment
Cryogenic crystal calorimeters are among the most competitive detector technologies for future neutrinoless double beta decay (0νββ) experiments. The dual readout of photon and thermal signals based on Transition Edge Sensors (TES) is essential for future large-scale deployment of these calorimeters. The quality and thickness of the superconducting thin films, as the core component of the TES, will affect the detector's sensitivity. In this study, we systematically investigate the relationship between the thickness of superconducting tungsten thin films and their grain size, resistivity, stress, and transition temperature. The results reveal that an optimal film thickness yields larger grains while minimizing both the resistivity and transition temperature of the film.
Speaker: 宇 王 (北京师范大学) -
202
Fast optical photon-number-resolving detector with iridium transition edge sensor
The transition edge sensor (TES) is a microcalorimeter that exploits the sharp increase in resistance at the transition between superconducting and normal conducting states. This steep transition characteristic enables even small energy depositions to produce large changes in resistance, resulting in sufficiently large current signal generation. TES technology has been primarily developed for X/gamma-ray detectors used in high-resolution spectroscopy applications. More recently, our research group has focused on developing smaller TES devices aiming for photon-number-resolving measurements in the near-infrared (NIR) wavelength ranges.
The optical TES has a smaller sensitive area to reduce its heat capacity and hence enables high energy resolution. The sensitive area is normally around 10 micrometers square, which is enough for obtaining the lights from single-mode optical fibers.
Our optical TESs are made of thin Iridium films, which have transition temperatures of around 300 mK. The fabricated devices are cooled down by adiabatic demagnetization refrigerator (ADR) or dilution refrigerator (DR) to around 100 mK. The Joule-heating from a TES and the cooling by the refrigerator are balanced and hence the TES is stabilized at its transition temperature. TES devices are irradiated by pulsed laser sources at the room temperature through the optical fibers which are wired inside the refrigerators. Our TES showed the energy resolution of around 0.4 eV and successfully showed photon number resolving capabilities in NIR wavelength regions. We are currently working on devices with fast timing capabilities aiming for wide applications.Speaker: Dr Yuki Mitsuya (The University of Tokyo) -
203
Superconducting Qubits as Particle Detectors
Recent years have seen growing concerns in the scientific community about the sensitivity of superconducting qubits to ionizing radiation. Particle interactions in the chip substrate produce phonons that reach the superconductor and break Cooper pairs, producing quasiparticles that can cause a drop in the decay time of the qubit.
Previous studies have already proven that radioactivity affect the performance of superconducting quantum circuits [1], will be a limit for the energy-relaxation time of next-generation qubits [2] and induce correlated errors in multi-qubit chips that could make present-day error correction algorithms fail [3, 4].
Despite being a concern for quantum computing experiments, the sensitivity of superconducting qubits to radioactivity is also an opportunity for the development of a novel particle detector. I will present the research activity carried out at the Gran Sasso National Laboratory (LNGS), Italy, where for the first time a superconducting qubit has been used for the detection of MeV-scale gamma particles [5]. To better disentangle ionizing radiation from other decay mechanisms, measurements were done in a deep-underground facility in the Hall C of LNGS underground laboratory. The facility is surrounded by 1.4 km of rock that acts as a natural shield for cosmic rays, and we implemented a lead and copper shield for suppressing the flux of environmental gammas. This configuration allowed us to characterize the qubit in an unprecedented low-radioactivity environment. We then exposed the qubit to Th sources with different activities and compared the results.
We observed that when the qubit was exposed to the Th sources, sudden increases in their decay rate would occur. Each of these events lasted a few milliseconds, and their rate increased linearly with the activity of the sources, confirming that they are radiation-induced.REFERENCES
1. Cardani et al., Reducing the impact of radioactivity on quantum circuits in a deep-underground facility, Nat Commun 12, 2733 (2021), https://doi.org/10.1038/s41467-021-23032-z
2. Vepsäläinen et al., Impact of ionizing radiation on superconducting qubit coherence, Nature 584, 551-556 (2020), https://doi.org/10.1038/s41586-020-2619-8
3. Wilen et al., Correlated charge noise and relaxation errors in superconducting qubits, Nature 594, 369-373 (2021), https://doi.org/10.1038/s41586-021-03557-5
4. McEwen et al., Resolving catastrophic error bursts from cosmic rays in large arrays of superconducting qubits, Nat. Phys. 18, 107-111 (2022), https://doi.org/10.1038/s41567-021-01432-8
5. De Dominicis et al., Evaluating radiation impact on transmon qubits in above and underground facilities, arXiv:2405.18355, https://doi.org/10.48550/arXiv.2405.18355Speaker: Alberto Ressa (INFN-Roma1)
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199
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Coffee break International Conference Center
International Conference Center
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Dark Matter and Its Detection: parallel session 6A Conference Room F2-R1
Conference Room F2-R1
Convener: Masaki Yamashita (Kavli IPMU, the University of Tokyo)-
204
Search for Light Dark Matter with XENONnT
The primary goal of the XENONnT experiment is the direct detection of Weakly Interacting Massive Particles (WIMPs), with a projected sensitivity improvement of an order of magnitude over XENON1T. In this talk, I will present recent results from the search for light dark matter using both scintillation-ionization and ionization-only channels with lowered detection threshold. These complementary analyses set world-leading constraints on dark matter–nucleon and dark matter–electron scattering cross sections. In the relevant mass range, the sensitivity reaches the so-called "neutrino fog"—a regime where coherent neutrino scattering produces irreducible backgrounds that mimic the signal of light dark matter interactions with xenon nuclei.
Speaker: Shenyang Shi (Columbia University) -
205
Sub-keV dark photon search with S2-only data in PandaX4T
The PandaX-4T experiment has achieved significant progress in ultra-low energy regions. Here, we present the first search for dark photon signals in the 0.1 - 1 keV energy range, previously unexplored by PandaX-4T. Using Run0+Run1 S2-only data, we set competitive constraints on the kinetic mixing parameter for dark photon masses in the range of 0.1 - 1 keV. This analysis extends the detection sensitivity to sub-keV physics, complementing the existing results from the PandaX-4T experiment.
Speaker: Dr Shuaijie Li (Shanghai Jiao Tong University) -
206
Search for new physics in low energy electron recoil signals in LZ WS2022+2024 combined dataset
LUX-ZEPLIN (LZ) is a direct detection dark matter experiment located at the Sanford underground research facility in Lead, South Dakota, USA. LZ utilizes a dual-phase time projection chamber containing 7 tonnes of active xenon surrounded by veto systems to search for signals induced by WIMP dark matter candidates. Recently, the experiment announced world-leading WIMP results achieved over 280 live days of science operation. Besides its leading sensitivity to WIMPs, LZ is also sensitive to other dark matter candidates and new physics beyond the Standard Model using electronic recoil (ER) signatures. In this talk, I will present results of the LZ search for new physics leading to ER events based on an exposure of 4.2±0.1 tonne-years. Our search includes several models, including solar axion-like particles, hidden photons, mirror dark matter models, bosonic dark matter absorption, and the exotic electromagnetic interactions of solar neutrinos.”
Speaker: YONGHENG XU (Universitetet i Oslo/UCLA) -
207
Searching for MeV-scale Axion-like Particles and Dark Photons with PandaX-4T
Axion-like particles (ALPs) and dark photons (DPs) are viable dark matter particle candidates.We have searched for possible ALP/DP signals in the PandaX-4T liquid xenon detector using 440 kg$\cdot$yr of data. A binned likelihood fit is constructed to search for possible mono-energetic peaks induced by the absorption processes between ALPs/DPs and atomic electrons of xenon. A detailed temporal model of decays associated with xenon isotopes is introduced to constrain the number of background events. We have established the most stringent exclusion limits for most ALP/DP masses across the range of 150 keV/$c^2$ to 1 MeV/$c^2$, which is particularly significant within the mass range of 150–400 keV/$c^2$.
Speaker: Tao Li (Shanghai Jiao Tong University) -
208
Search for axions and other new physics signals with PandaX-4T
PandaX-4T, a large-scale liquid xenon detector operating at the China Jinping Underground Laboratory, features ultra-low background, high sensitivity, and excellent energy resolution, making it a powerful platform for probing physics beyond the Standard Model. In this talk, I will present our latest results on the search for axions and axion-like particles (ALPs), including solar axions, axions with electron couplings, and ALP dark matter, based on data from PandaX-4T. In addition, we investigate other potential signatures of low mass dark matter even to sub-MeV level through solar boosted mechanism. The resulting constraints are competitive with leading global results and highlight the broad potential of PandaX-4T in the search for new fundamental physics.
Speaker: xiaopeng Zhou (Beihang University) -
209
First Search for Ultralight Dark Matter Using a Magnetically Levitated Particle
We performed the first search for ultralight dark matter using a magnetically levitated particle. A sub-millimeter permanent magnet was levitated in a superconducting found with a measured force sensitivity of 0.2 fN/$\sqrt{\text{Hz}}$. We find no evidence of a signal and derive limits on dark matter coupled to the difference between baryon and lepton number, B−L, in the mass range $(1.10360–1.10485)×10^{−13}$ eV. Our most stringent limit on the coupling strength is $g_{B−L} \lt 2.98 \times 10^{−21}$. We propose the POLONAISE (Probing Oscillations using Levitated Objects for Novel Accelerometry in Searches of Exotic physics) experiment, featuring short-, medium-, and long-term upgrades that will give us leading sensitivity in a wide mass range and demonstrating the promise of this novel sensing technology in the hunt for dark matter.
This talk will review our recent PRL while discussing the general landscape of mechanical sensing for dark matter.
Speaker: Chris Tunnell (Rice University) -
210
Search for Dark Matter with Levitated Ferromagnetic Spin Sensor
In this talk, I will focus on is the levitated ferromagnetic spin sensor, which offers significant advantages due to its weak coupling with the environment, enabling superior noise isolation[1][2]. Additionally, the strong spin correlation within the ferromagnetic sensor provides promising noise suppression and signal enhancement capabilities, particularly in experiments probing the low-frequency regime. These features make levitated ferromagnetic spin sensors highly sensitive and well-suited for both new physics searches and real-world applications.
[1] F. Ahrens., W.Ji, D. Budker et al, Levitated Ferromagnetic Magnetometer with Energy Resolution Well Below ℏ. Phys. Rev. Lett. 134(11), 110801(2025).
S. Kalia, D. Budker; D. F. J Kimball, W. Ji et al, Ultralight Dark Matter Detection with Levitated Ferromagnets. Phys. Rev. D 2024, 110 (11), 115029（2025）.Speaker: Wei Ji (Peking University)
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204
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Dark Matter and Its Detection: parallel session 6B Conference Room F2-R2
Conference Room F2-R2
Convener: Kenny Chun Yu Ng (The Chinese University of Hong Kong)-
211
Progress of the COSINE-100U experiment
COSINE-100, a direct dark matter search experiment, operated from October 2016 to March 2023 at the Yangyang Underground Laboratory, Korea, using 106 kg of low-background NaI(Tl) scintillating crystals. It is now being upgraded to COSINE-100U by relocating to the newly constructed Yemilab in Jeongseon, Korea. In the upgraded version, a novel encapsulation process has been applied to the primary detector, the NaI(Tl) crystal, resulting in an improved light yield of approximately 35%. The upgraded experiment is scheduled to begin operation in mid-2025. In this presentation, we will report the current status of COSINE-100U and its plans.
Speaker: Doohyeok Lee -
212
Advanced NaI detectors for Dark Matter search and other applications: the ANAIS+ project
NaI(Tl) is a highly interesting target for dark matter searches due to its high light yield, which enables low energy thresholds, the combination of heavy and light nuclei, and the 100% presence of isotopes with nuclear spin and an unpaired proton. Moreover, it is the target material of the only experiment to date that has reported a positive signal (DAMA/LIBRA), and an ultra-low energy threshold search could resolve some of the remaining systematic uncertainties in the direct refutations involving the same target. Another interesting application is the search for coherent elastic neutrino-nucleus scattering, which also requires a very low energy threshold. A significant limitation in the use of these scintillators arises from the light noise introduced by the photomultiplier tube (PMT). The ANAIS+ experiment proposes to overcome this limitation by replacing PMTs with SiPMs and operating at cryogenic temperatures near 100 K, which enhances light emission when using pure NaI. In this talk, we will present the status of the first ANAIS+ prototype and discuss the prospects of this technique.
Speaker: Maria Martinez (CAPA-Universidad de Zaragoza) -
213
Dark matter annual modulation analysis with combined nuclear and electron recoil channels
The DAMA/LIBRA (DL) experiment remains the only direct detection effort reporting a positive annual modulation (AM) signal attributed to WIMP-nucleus ($\chi$N) interactions, despite several decades of intensive searches in the dark matter sector [1, 2]. In recent years, several analyses employing both time-integrated and AM approaches have placed significant constraints on, and in many cases excluded, the DL positive signal claim. Our current analysis [3] broadens the AM investigation by simultaneously considering dark matter-electron ($\chi$e) interactions $-$ addressed in both long-range and short-range frameworks [4] alongside the standard $\chi$N interaction channel. To enhance the credibility of the study, we investigated single- and two-component $\chi$'s interaction scenarios for both $\chi$N and $\chi$e recoil channels. Despite achieving better statistical fits, these scenarios do not reconcile with the DL signal and are ruled out by null results from other contemporary experiments. The CDEX experiment, with its low detection threshold, is particularly sensitive to long-range interactions, thereby placing tight constraints, whereas XMASS offers more stringent bounds on short-range interactions due to its high exposure and large target mass. In addition to the current analysis, we also discuss the future sensitivity to both long-range and short-range $\chi$e interactions, as well as $\chi$N interactions, in light of the recently achieved 150~eV ionization threshold using a $p$-type point-contact germanium detector at the TEXONO experiment [5].
References:
[1] R. Bernabei et al., The DAMA/LIBRA apparatus, Nucl. Instrum. Meth. A 592, 297 (2008).
[2] D. Buttazzo et al., Annual modulations from secular variations: relaxing DAMA?, JHEP 2020, 137 (2020).
[3] H. B. Li et al., Dark Matter Annual Modulation Analysis with Combined Nuclear and Electron Recoil Channels, Phys. Rev. D 111, 083035 (2025).
[4] M. K. Pandey et al., Constraints from a many-body method on spin-independent dark matter scattering off electrons using data from germanium and xenon detectors, Phys. Rev. D 102, 123025 (2020).
[5] S. Karmakar et al. (TEXONO Collaboration), New Limits on the Coherent Neutrino-Nucleus Elastic Scattering Cross Section at the Kuo-Sheng Reactor-Neutrino Laboratory, Phys. Rev. Lett. 134, 121802 (2025).Speaker: Dr Manoj Kumar Singh (Institute of Physics, Academia Sinica, Taipei, 115201, Taiwan) -
214
First cryogenic SiPM readout of a NaI(Tl)-based dark matter detector with the ASTAROTH project
One of the most exciting quests in fundamental physics is the search for dark matter, which continues to see growing worldwide efforts across several theories and experimental techniques. Among these, NaI(Tl) scintillating crystals stand out, as they are used to observe the direct interaction of dark matter particles via nuclear recoils of a few keV. A long-lasting, but so far unconfirmed, positive result obtained at the Gran Sasso National Laboratory calls for further investigation. The ASTAROTH project in Milan is developing a cryogenic NaI(Tl)-based detector, where light is read for the first time using large-area SiPM matrices. The ASTAROTH innovative detector design has the potential to surpass the limitations of current-generation experiments, enabling the exploration of sub-keV energy recoils where a significant fraction of the dark matter signal may be waiting to be uncovered. The first phase of the project concluded in 2024 with the first successful data taking campaign. We report about the results and performance of the detector as well as the developments planned within the second phase of the project for the next three years.
Speaker: Davide D'Angelo (Univerisità degli Studi di Milano e INFN) -
215
Pulse Shape Discrimination Measurement of CsI(Tl) Scintillator with Green-Extended Photocathode PMTs
The KIMS experiment previously used CsI(Tl) crystals for dark matter searches, employing pulse shape discrimination (PSD) to distinguish nuclear recoil signals from electron recoil backgrounds. However, the sensitivity was limited by a relatively low light yield of approximately 5 photoelectrons (PE) per keV, mainly due to the low quantum efficiency of conventional PMTs in the green emission range characteristic of CsI(Tl). Recent advances by Hamamatsu Photonics have led to the development of high quantum efficiency PMTs with green-extended photocathodes. By coupling CsI(Tl) crystals with two Hamamatsu R11934 1-inch PMTs, we have achieved a significantly improved light yield of up to 11 PE/keV. Since PSD performance strongly depends on photon statistics, this enhancement is expected to substantially improve background discrimination power. In this presentation, we report on the light yield and PSD performance of a CsI(Tl) detector coupled with two high quantum efficiency PMTs. We also present results from PSD measurements using a neutron generator to compare nuclear and electron recoil responses. Additionally, we discuss the design considerations of high-light-yield CsI(Tl) detectors optimized for future dark matter searches.
Speaker: Sedong Park (Kyungpook National University) -
216
Scintillation Characteristics of an Undoped CsI Crystal with SiPM Readout for Dark Matter Detection
Undoped CsI crystals are promising target materials for dark matter detection due to their high scintillation light yield at cryogenic temperatures. At liquid nitrogen temperature (~77 K), they emit more than 80,000 photons/MeV, making them suitable for detecting low-energy nuclear recoils. In this study, we investigated the scintillation properties of an undoped CsI crystal coupled with two silicon photomultipliers (SiPMs), which are compact and compatible with low-temperature operation. We measured the temperature-dependent light yield and scintillation decay time from room temperature down to 77 K. Based on the measured performance, we also evaluated the dark matter detection sensitivity of the undoped CsI–SiPM system. In this presentation, we will discuss the experimental results and assess the potential of this detector configuration for future low-threshold dark matter searches.
Speaker: Wonkyung Kim (University of Science & Technology (UST), IBS School) -
217
The event discrimination in the bulk region of the point-contact germanium detector
The p-type point-contact high-purity germanium detector is a critical tool for rare-event searches, including direct dark matter detection, coherent elastic neutrino-nucleus scattering, and neutrinoless double-beta decay, owing to its ultralow detection threshold, ultralow intrinsic background, and excellent energy resolution.
In the CDEX-1B detector, we observed anomalous bulk events with an extremely fast rise time, which could be closely related to the background. Here, we developed a pulse shape discrimination method combining pulse shape simulation and reconstructed source experiment signatures, to extract fast bulk events from normal bulk events. Calibration data and the distribution of X-rays generated by intrinsic radioactivity verified that the fast bulk events experienced a single hit near the passivation layer.
This study demonstrates the detector’s capability of single-hit bulk spatial resolution, and thus provides a background removal technique in future rare-event experiments.Speaker: Renmingjie Li (四川大学)
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211
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Gravitational Waves: parallel session 6 Conference Room F1-R3
Conference Room F1-R3
Convener: Huaike Guo (中国科学院大学（ICTP-AP）)-
218
Gravitational waves from preheating in the early Universe
Preheating stage after inflation can cause a significant effect of graviton production. These gravitons at high frequencies can contribute to the dark radiation component which is constrained from CMB data. Gravitons at lower frequencies would produce an inevitable stochastic gravitational wave background which may be probed in future ground-based and space-based detectors. We show that out of equilibrium effects during reheating can enhance the graviton production.
Speaker: Anna Tokareva (国科大杭州高等研究院) -
219
Search for an isotropic Gravitational Wave Background with ground based detectors and cosmological implications
The gravitational wave background (GWB) is a superposition of weak, independent and unresolved gravitational wave (GW) sources. It can be sourced by both astrophysical and cosmological sources, among which we find unresolved compact binary coalescences, supernovae, first order cosmological phase transitions and cosmic strings. Since the beginning of its observational runs, the LIGO-Virgo-KAGRA (LVK) collaboration has been searching for the GWB, utilizing a cross-correlation technique. We have not made a GWB detection thus far. However, we have succeeded in establishing upper limits on the GWB's amplitude, providing invaluable insights into the model parameters governing its various sources. In this presentation, I will provide an overview of the GWB, explain how search for an isotropic GWB in the LVK collaboration and the multitude of data analysis challenges we encounter. Furthermore, I will delve into the implications of our searches for cosmological sources. Finally, I will explore the exciting prospects for future detection with third generation detectors, paving the way for groundbreaking discoveries in gravitational wave astronomy.
Speaker: Alba Romero-Rodríguez -
220
Enhancing Taiji’s Estimation on Galactic Binaries and Instrumental Noises Against Non-Stationaries with Time-Frequency Domain Formalism
The data analysis of future space-based gravitational wave detectors like LISA and Taiji face significant challenges due to non-stationarities in their data, originating from time-varying astrophysical confusion foregrounds and instrumental noise drifts, which compromise traditional Fourier-domain analysis methods. In this work, we address this challenge by proposing a unified formalism based on Short-Time Fourier Transform (STFT), in order to enhance the estimation of Galactic binary (GB) signal parameters and instrumental noise characteristics admist non-stationarities. Our approach segments data into locally stationary intervals, incorporates windowing to mitigate spectral leakage, derives GPU-accelerated waveform templates and noise spectral models compatible with Taiji’s realistic orbits, and perform parameter estimations using time-frequency domain statistics. Tests on simulated data via a ”noise-agnostic workflow” demonstrate that, compared to conventinoal Fourier-domain methods, our STFT approach yields more unbiased estimation for GB signals, and provides tighter constraints on instrumetal noises. These results confirm the framework’s robustness against noise drifts (and potentially data gaps) while maintaining computational efficiency, highlighting its potential for future global analysis pipelines, especially in discriminating anisotropic stochastic GW backgrounds and instrumental noises. The pre-print of this work can be found at arxiv:2506.10599.
Speaker: Minghui Du (Institute of Mechanics, Chinese Academy of Sciences) -
221
Dawning of a new era in gravitational wave data analysis: Unveiling cosmic mysteries via artificial intelligence — A systematic review
Gravitational wave data analysis (GWDA) faces significant challenges due to high-dimensional parameter spaces and non-Gaussian, non-stationary artifacts in the interferometer background, which traditional methods have made significant progress in addressing but continue to face limitations. Artificial intelligence (AI), particularly deep learning (DL) algorithms, offers potential advantages, including computational efficiency, scalability, and adaptability, which may complement traditional approaches in tackling these challenges more effectively. In this review, we explore AI-driven approaches to GWDA, covering every stage of the pipeline and presenting first explorations in waveform modeling and parameter estimation. This work represents the most comprehensive review to date, integrating the latest AI advancements with practical GWDA applications. Our meta-analysis reveals insights and trends, highlighting the transformative potential of AI in revolutionizing gravitational wave research and paving the way for future discoveries.
Speaker: 赵 天宇 (中国科学院力学研究所) -
222
Accelerating Stochastic Gravitational Wave Backgrounds Parameter Estimation in Pulsar Timing Arrays with Flow Matching
title:Accelerating Stochastic Gravitational Wave Backgrounds
Parameter Estimation in Pulsar Timing Arrays with Flow Matchingabstract:Pulsar timing arrays (PTAs) are essential tools for detecting the stochastic gravitational wave background (SGWB), but their analysis faces significant computational challenges. Traditional methods like Markov-chain Monte Carlo (MCMC) struggle with high-dimensional parameter spaces where noise parameters often dominate, while existing deep learning approaches have so far been validated on synthetic datasets or require training on the full pulsar set, incurring substantial computational and memory costs. We propose a flow-matching-based continuous normalizing flow (CNF) for efficient and accurate PTA parameter estimation. By focusing on the 10 most contributive
pulsars from the NANOGrav 15-year dataset, our method achieves posteriors consistent with MCMC, with a Jensen-Shannon divergence below 10−2 nat, while reducing sampling time from 50 hours to 4 minutes. Powered by a versatile embedding network and a reweighting loss function, our approach prioritizes the SGWB parameters and scales effectively for future datasets. It enables precise reconstruction of SGWB and opens new avenues for exploring vast observational data and
uncovering potential new physics, offering a transformative tool for advancing gravitational wave astronomy.Speaker: Bo Liang (中国科学院力学研究所) -
223
Impact of Massive Black Hole Binaries Source Confusion on Uncertainties of Parameters Estimation in Space-based Gravitational Wave Detection for the TaiJi Mission
We systematically investigate the impact of source confusion on parameter estimation for massive black hole binaries (MBHBs) in the context of the Taiji space-based gravitational wave mission. Source confusion, arises from simultaneous overlap of signals in both time and frequency domains, can degrade the accuracy of parameter recovery. To assess this effect, we simulate MBHB populations using three representative models and estimate the prevalence of overlapping events. Assuming a detection rate of 50 events per half-year, we find that genuine source confusion is relatively rare, with only 0.16 to 2.1 overlapping events expected per half-year, depending on the model. We quantify parameter uncertainties using both the Fisher information matrix and Markov chain Monte Carlo (MCMC) techniques. Employing the IMRPhenomD waveform model, as conventionally used in the literature, we show that parameter uncertainties can increase significantly, while the inclusion of higher-order modes (HMs) in the waveform model effectively mitigates this degradation. The uncertainty ratio $\gamma - 1$ can exceed $\mathcal{O}(10^1)$ even when higher-order modes (HMs) are included, provided that the relative chirp mass difference $\Delta \mathcal{M}_z / \mathcal{M}_z$ is below 0.2\%, while such strong degeneracies occur in fewer than 0.14\% in all three population models. MCMC results not only confirm Fisher’s forecasts but also reveal that HMs help break key parameter degeneracies, with or without signal overlap. These findings underscore the importance of incorporating HMs in waveform modeling for robust and accurate inference in future space-based gravitational wave observations.
Speaker: Qing Diao (International Centre for Theoretical Physics Asia-Pacific,University of Chinese Academy of Sciences)
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218
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High-Energy Astrophysics and Cosmic Rays: parallel session 6 Conference Room F1-R2
Conference Room F1-R2
Convener: Siming Liu (西南交通大学)-
224
Recent results of the Tibet AS$\gamma$ experiment
The Tibet Air Shower Array is located in Yangbajing, China, and has been operated since 1990. Its air shower array covers a geometrical area of 65,700 m$^2$ by featuring about 600 plastic scintillation detectors and captures air showers produced by cosmic rays with energies from 10$^{12}$ eV to more than 10$^{15}$ eV. In particular, since the installation of an underground muon detector array in 2014, the experiment has been performing observations sensitive to the celestial gamma rays with energies reaching beyond 10$^{14}$ eV, the sub-PeV energy range. The use of the underground muon detector combined with the surface air shower array resulted in the first detections of sub-PeV gamma rays from the Crab Nebula and sub-PeV Galactic diffuse gamma rays, and identifications of some PeVatron candidates, such as SNR G106.3+2.7. This talk will mainly focus on how the Tibet AS$\gamma$ experiment has been contributing to the development of sub-PeV gamma-ray astronomy and present some interpretations of the results accounting for those given by other gamma-ray observatories.
Speaker: Sei Kato (Institut d'Astrophysique de Paris) -
225
A brief overview of UHE gamma-ray astronomy
Ultra-High Energy (UHE, >0.1 PeV) γ-ray astronomy has emerged as a pivotal field in astrophysics, driven by the discovery of 43 UHE sources. These sources are critical for identifying PeVatrons—astrophysical accelerators capable of producing particles at PeV energies—which are linked to the origin of cosmic rays (CRs) near the "knee" of the CR spectrum (~1–3 PeV). This presentation provides a brief overview of these UHE sources and examines their implications for pinpointing potential PeV CR origins as revealed by observational data.
Speaker: Shaoqiang Xi (IHEP) -
226
A giant ultra-high-energy gamma-ray emitting region associated with a millisecond pulsar
In this talk, I will present the discovery of a giant peanut-shaped ultra-high-energy (UHE) γ-ray emitting region using data from the Large High Altitude Air Shower Observatory (LHAASO). The emission, located in isolation below the Galactic plane at a Galactic latitude b ≃ −17.5◦, features two prominent hot spots embedded in a uniform rectangular structure covered a large region of 1°×5°, spanning an energy range from approximately 10 TeV to several hundreds TeV.
Only a very aging millisecond pulsar (MSP) J0218+4232 is found spatially associated with the emission region. This is the first time for an MSP to be possibly responsible to emission of gamma rays with such a specific energy spectral distribution measured only above 0.01 PeV with the most energetic photon at ~0.7 PeV. Other implications to this region will be also discussed which are actually mostly potential challenges.Speaker: Zhe Li -
227
Spectrum and Morphology of the Ultra-High-Energy Source LHAASO J2018+3651
The LHAASO J2018+3651 region is one of the brightest sources in the Cygnus region at TeV energies. Photons with energies up to 0.27 PeV from this source have been detected with the Large High Altitude Air Shower Observatory (LHAASO) and here we present a detailed study of this region using more data from LHAASO. This analysis resolves the region into six sources: LHAASO J2018+3641, LHAASO J2019+3649, LHAASO J2021+3654, LHAASO J2016+3712, LHAASO J2013+3610 and LHAASO J2027+3657. In this work, we conduct a detailed analysis of the morphology and energy spectrum of these six sources, and discuss their possible counterparts and radiation mechanisms.
Speaker: Dr Chao Hou (IHEP) -
228
Measurement of diffuse gamma-ray emission based on source-deduction method at Galactic plane by LHAASO
The diffuse Galactic gamma-ray emission, mainly produced via interactions between cosmic rays and the interstellar medium and/or radiation field, is a crucial probe of the distribution, propagation, and interaction of cosmic rays in the Milky Way. Using the source deduction method and the latest data from WCDA and KM2A, we have preliminarily measured this emission and present the energy spectra of diffuse emission in the Inner Galaxy region ( 15°< l <125°, |b| < 5°) and the Outer Galaxy region (125°< l < 235°, |b| < 5°). Additionally, we found that the spatial distribution of the diffuse emission deviates from the Planck Dust map, suggesting distinct astrophysical origins. These findings offer valuable insights into the properties of diffuse gamma-ray emissions and highlight the need for refined methodologies to better understand the underlying astrophysical processes.
Speaker: Dr Rui Zhang (PMO) -
229
A leptonic view on the UHE Gamma-ray emission from V4641 Sgr
Microquasars are binary systems which are composed of compact objects and stars, launching (sub-)relativistic jets. Recently, the microquasar V4641 Sgr is detected with extended ultra-high-energy(UHE) emission by LHAASO and HAWC. Interestingly, its spectrum follows a power-law function continuing up to 0.8 PeV, and the morphology appears a puzzling elongated structure which is misaligned with its radio jet at small scale. In this work, we propose that the elongated UHE emission from V4641 Sgr could originate from the inverse Compton radiation of electrons with a very hard spectrum, which may result from shear acceleration mechanism in the quasi-steady jet driven by V4641 Sgr. Under this model, the magnetic field within the jet is constrained to a $\mu G$ level, although it depends on the transverse radius of the jet. We also calculate the corresponding X-ray synchrotron emission from the same electron population, predicting the potential range of non-thermal X-ray flux of the source. The recent observation by XRISM toward the central part of the UHE source may pose a constraint on the model parameters. In the future, a full coverage of the source by sensitive X-ray instrument may provide a critical test of the model.
Speaker: Suyu Wan (Nanjing University) -
230
AugerPrime, the upgrade of the Pierre Auger Observatory: current status and data taking
The Pierre Auger Observatory, designed for research of ultra-high-energy cosmic rays (UHECRs), has been collecting data since early 2004 and was completed in 2008. It is located at 1400 m above sea level near Malargüe, Mendoza, Argentina, covering a vast plain of about 3000 square kilometers, known as the Pampa Amarilla. The Observatory consists of a hybrid detector, composed of 1660 water-Cherenkov stations, which form the Surface Detector and 27 peripheral atmospheric fluorescence telescopes, which comprise the Fluorescence Detector. Over time, the Observatory has undergone enhancements with various R&D prototypes. Since 2016, it has been subjected to a significant and well-structured upgrade. The installation of different detectors - including the Radio Detector (RD), the Surface Scintillator Detectors (SSD), the Underground Muon Detector (UMD) - plus a Small PMT (SPMT) in the existing water-Cherenkov stations, in addition to the Upgraded Unified Board (UUB) to handle all the newly installed systems, forms the whole upgrade, known as AugerPrime. As the commissioning of the final components of AugerPrime approaches its completion and the upgraded array becomes fully operational, the Observatory has started acquiring data with the enhanced instrumentation. The entire area is now equipped with SSDs, SPMTs, UUBs, and RDs, while the deployment of the UMD is nearing completion. In this contribution, we provide a general overview of AugerPrime, highlighting its potential to deepen our understanding of the nature and origin of UHECRs. We also discuss the current status of the Observatory, focusing on performance, data quality, and first results.
Speaker: Rossella Caruso (Department of Physics and Astronomy "E.Majorana" - University of Catania & INFN-CT, Italy)
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224
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Neutrino Physics and Astrophysics: parallel session 6A North Hall #1
North Hall #1
Convener: Masaki Ishitsuka (Tokyo University of Science)-
231
RED-100: Results and status
The RED-100 is a two-phase noble gas emission detector built for observation of coherent elastic neutrino-nucleus scatteing (CEvNS) in reactor antineutrino interactions with matter. The first data taking run with LXe target was carried out at the Kalinin nuclear power plant in 2022, and the final results are given and discussed. The RED-100 experiment is currently in preparation for Phase II with LAr. The laboratory tests have shown that the LAr is a much better working medium from the point of view of the background caused by the delayed electrons.
Challenges and technical solutions of detection low-energy signals in a ground-level conditions with the RED-100 detector are discussed.Speaker: Ekaterina Kozlova (Westlake University, NRNU MEPhI) -
232
First performance of the Ricochet experiment at ILL
The Ricochet experiment aims at measuring the coherent elastic neutrino-nucleus scattering (CEνNS) of reactor antineutrinos at the Institut Laue-Langevin, ILL (Grenoble, France). Ricochet employs two detector technologies to measure the CEνNS: (1) germanium cryogenic calorimeters with neutron-transmutation-doped thermistors (called CryoCube); (2) cryogenic calorimeters with a superconducting target and a transition-edge sensor readout (called Q-Array). The CryoCube exploits a combined readout of phonons and ionization to identify nuclear recoil events and reject other backgrounds (electron recoils). The Q-Array will use pulse shape discrimination related to the different timescales of quasiparticle recombination and phonon relaxation for electron- and nuclear-recoils respectively. In 2024, the Ricochet experiment was commissioned at the ILL with a mini-CryoCube detector, composed by three 42-gram germanium detectors. The results in terms of detector performance and background levels achieved during this commissioning phase will be presented in this contribution.
Speaker: Valentina Novati (CNRS LPSC) -
233
Status and prospects of the CICENNS Experiment
The CICENNS (CsI detector for Coherent Elastic Neutrino Nucleus Scattering) experiment aims to construct a CsI(Na) detector array with total mass of 300 kg, located at the China Spallation Neutron Source, for the precise measurement of coherent elastic neutrino-nucleus scattering. In this talk, I will present the plan, status, and physics goals of CICENNS.
Speaker: Xiang Xiao (Sun Yat-sen University) -
234
Progress of CryoCsI detector R&D from COHERENT
This presentation will detail the latest advancements in the development and characterization of a 6.6 kg proto-type CryoCsI detector, comprising two 3.3 kg cesium iodide (CsI) crystals operated at around 90K. Key performance metrics of the detector, including light yield optimization, spatial uniformity of signal response, and long-term stability under sustained cryogenic conditions, will be discussed to establish its viability for large-scale deployment. Additionally, results from a precision quenching factor measurement of pure CsI at low temperatures will be presented, providing critical insights into the scintillation efficiency of the material in recoil-based detection scenarios. Comprehensive steady-state background measurements, conducted to identify and mitigate noise sources, will be highlighted to demonstrate the detector’s capability to operate in low-background environments. Finally, projections for the expected event rate of coherent elastic neutrino-nucleus scattering (CEvNS) interactions and the detector’s resulting physical sensitivity to beyond-Standard-Model physics will be outlined, underscoring its potential to advance neutrino and dark matter research in upcoming phases of the experiment.
Speaker: 苏 晨光 (中国科学院大学) -
235
Status and prospects of RECODE program with PPC Germanium detector
The RECODE (Reactor neutrino COherent scanning Detection Experiment) uses two sets of high-purity germanium arrays to accurately measure the CEvNS process of reactor neutrinos. The high-purity germanium technology used comes from the PPC germanium detector technology developed by CDEX in dark matter experiments. The currently confirmed experimental site is located at Sanmen Nuclear Power Plant (NPP) in Zhejiang Province, China. In the RECODE project, two experimental sites with different distances to the core will be set up to carry out joint measurements. The far site is approximately 22 m away from the 3.4 GWth reactor core, and the near site is about 10 m away. This will endow RECODE with advantages such as a high neutrino flux (~5×10^13 ν/cm2/s) and the reduction of errors through joint measurements. In this talk, the status and prospects of RECODE will be described and discussed.
Speaker: Yufeng Wang -
236
RELICS: Search for Coherent Elastic Neutrino-Nucleus Scattering from reactor neutrinos using LXeTPC
The measurement of the Coherent Elastic Neutrino-Nucleus Scattering (CE$\nu$NS) offers a unique probe of the properties of neutrinos and new physics beyond the Standard Model.
However, large amount of background from cosmic rays and environmental radiations in the low-energy region makes the detection of CE$\nu$NS signals from reactor neutrino challenging.
The Liquid Xenon Time Projection Chamber (LXeTPC), which demonstrates good performance in dark matter detection and shows great potential in detecting nuclear recoil events within the relevant energy region (<1 keV), is a promising technology for detecting CE$\nu$NS signals. Reactor neutrino Liquid xenon Coherent Scattering experiment (RELICS) proposes to employing this technology to detect CE$\nu$NS caused by $\sim$MeV neutrinos from the reactors. This presentation will introduce the latest developments of the RELICS experiment.Speaker: jiachen yu (ustc) -
237
Status of Neutrino-Nucleus Scattering Observations in the NEON Experiment
The Neutrino Elastic-Scattering Observation with NaI(Tl) (NEON) experiment is primarily designed to detect coherent elastic neutrino-nucleus scattering (CEνNS). Situated in the tendon gallery of the Hanbit Nuclear Power Plant in Yeonggwang, South Korea, the NEON experiment utilizes reactor neutrinos as a source for the neutrino interaction. Since its successful initiation in 2022, the experiment has been continuously collecting data utilizing six high-light-yield NaI(Tl) detectors of total 16.7 kg. Currently, approximately 780 days of reactor-on data and 220 days of reactor-off data are available for analysis, and data collection remains ongoing.
Recently, the NEON experiment has expanded its search also to include incoherent neutrino-nucleus scattering processes, which involve nuclear excitation, and the corresponding signal can be identified through the 57.6 keV gamma transition of Iodine.
We present recent analysis results on both coherent and incoherent neutrino-nucleus scattering.Speaker: Seo Hyun Lee -
238
Non-Standard Neutrino Interactions with Coherent Elastic Neutrino-Nucleus Scattering at TEXONO
Coherent Elastic Neutrino-Nucleus Scattering (CE$\nu$NS) is a tree-level neutral-current process described within the Standard Model (SM). CE$\nu$NS serves as a crucial channel for testing the SM of electroweak theory and exploring potential new physics at low energies. Since its first detection[1], significant efforts, including the TEXONO experiment, have focused on detecting and improving our understanding of this process. The TEXONO Collaboration conducts an intensive research program on low-energy neutrino physics at the Kuo-Sheng Nuclear Power Plant in Taiwan, detecting low-energy electron antineutrinos with high-purity germanium (Ge) detectors[2].
We present the first comprehensive NSI analysis of TEXONO CE$\nu$NS data, using both nPC-Ge(2016) and the recently upgraded pPC-Ge(2025)[3] detectors, which have threshold energies of 300 eV and 200 eV, respectively. Our study explores all possible NSI types – vector (V), axial-vector (A), scalar (S), pseudoscalar (P), and tensor (T) – through both a simplified model with light mediators and model-independent approaches. We demonstrate that TEXONO pPC-Ge data significantly improve the sensitivity over the earlier nPC-Ge data, and offer competitive constraints compared to other reactor neutrino experiments[4]. Our results highlight the critical role of CE$\nu$NS experiments in advancing neutrino physics and probing interactions beyond the SM.References
[1] D. Akimov et al. [COHERENT Collaboration], "Observation of Coherent Elastic Neutrino-Nucleus Scattering," Science 357, 6356, 1123 (2017).
[2] H. T. Wong et al., "Research program towards observation of neutrino-nucleus coherent scattering," J. Phys. Conf. Ser. 39, 266 (2006).
[3] S. Karmakar et al. [TEXONO Collaboration], "New Limits on Coherent Neutrino Nucleus Elastic Scattering Cross Section at the Kuo-Sheng Reactor Neutrino Laboratory.", Physical Review Letters, 134(12), 121802.
[4] S. Karadag et al. [TEXONO Collaboration], "Constraints on New Physics with Light Mediators and Generalized Neutrino Interactions via Coherent Elastic Neutrino Nucleus Scattering.", arXiv preprint, arXiv:2502.20007.
Speaker: Sevgi Karadağ (Academia Sinica & Istanbul Technical University)
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231
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Neutrino Physics and Astrophysics: parallel session 6B North Hall #2
North Hall #2
Convener: Christoph Wiesinger-
239
Updated background simulation and detector design for AMoRE-II
AMoRE-II aims to search for neutrinoless double-beta decay of $^{100}$Mo using cryogenic detectors based on an array of Li$_2^{100}$MoO$_4$ crystals. The first stage of the experiment will employ 90 LMO crystals (27 kg of $^{100}$Mo) in 2025, expanding to 360 crystals (155 kg $^{100}$Mo) for full-scale data taking in 2027. To achieve a target sensitivity of T$_{1/2}^{0\nu\beta\beta}$ > 4.5$\times$10$^{26}$ years, we aim for a background level below 1$\times$10$^{-4}$ ckky. A Geant4-based simulation framework has been developed to evaluate expected background contributions, currently estimated to be below 2$\times$10$^{-4}$ ckky. Major contributors include $^{226}$Ra in lead shielding and $^{222}$Rn in air. To mitigate these sources, we optimized material selection—using ultra-pure lead and copper replacements—and designed enclosures to minimize radon intrusion. Surface contamination on crystals and nearby components, such as copper holders and reflectors, was also addressed through improved handling, cleaning, and assembly protocols. These updates, supported by detailed simulations, have led to an optimized detector configuration that meets the stringent background requirements. We present the updated background estimates, simulation methodologies, design refinements, and ongoing strategies for further suppression as AMoRE-II prepares for full-scale operation.
Speaker: Eunju Jeon (Institute for Basic Science) -
240
OPOSSUM - Optimal Particle identification Of Single Site events with Underground MKIDs detectors
The goal of OPOSSUM is to discriminate for the very first time Single Site Events (SSE) from Multi Site Events (MSE) in mK calorimeters for rare events searches. The OPOSSUM project, funded by the European Research Council trough a Starting Grant in 2024, embarks on a transformative journey to push an order of magnitude forward the sensitivity of Neutrinoless double-beta decay (0νββ) experiments, a key process which, if observed, will redefine our comprehension of neutrinos and the physics beyond the Standard Model. Detecting 0νββ would not only confirm the Majorana nature of neutrinos could also enlighten us on the absolute neutrino mass scale and hierarchy.
At the heart of OPOSSUM is a novel discrimination strategy designed to positively identify 0νββ events (SSE), rejecting all other prominent background sources, as alpha and gamma interactions (MSE) in TeO2.
With its 33% isotopic abundance 130Te emerges as the leading 0νββ candidate, bypassing the need for the
now-challenged enrichment process. In OPOSSUM 12 CUORE prototype crystals will be outfitted with 6 Microwave Kinetic Inductance Detectors (MKIDs) along with existing thermistors and through integrated analysis, The OPOSSUM technique could reduce the CUORE background to below 10-4 counts/keV/kg/y, positioning it to probe the inverted hierarchy scenario corresponding to the 10 meV Majorana mass. In this contribution I will outline the innovative experimental technique of OPOSSUM, its potential and the first steps towards the implementation of MKIDs on TeO2.Speaker: andrei puiu (Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali del Gran Sasso) -
241
Search for double electron capture in Sn-112 using gamma-ray TES
Double electron capture (ECEC) is a second-order weak interaction
process in which two orbital electrons are captured simultaneously by a
nucleus. Its half-life serves as a sensitive probe for testing nuclear
structure models. To date, only ECEC in xenon-124 has been observed,
indicating the need for new experimental techniques. In this
presentation, we report a search for double electron capture in Sn-112
using transition edge sensors (TES). The use of gamma-ray TES with Sn
absorber allows us to search for ECEC reaction efficiently by detecting
X-rays and/or Auger electrons following ECEC. We will present the
current status of the measurement using 8-pixels TESs array with 0.8 mm
cubic tin absorbers, and will discuss the future sensitivity assuming
the increase of pixelization and fiducial volume.Speaker: Atsuto Takeuchi (RCNS, Tohoku University) -
242
Study of Li2MoO4 and Na2Mo2O7 crystals for 100Mo neutrinoless double beta decay search with cryogenic bolometers:
The novel molybdate crystals, Li2MoO4 (LMO) and Na2Mo2O7 (NMO), are popular used as absorbers in cryogenic phonon scintillating bolometers for 100Mo neutrinoless double beta decay search. The low temperature properties of LMO and NMO, including scintillation characteristics and specific heat, have been investigated experimentally. The excitation spectrum and light yield are measured ranging from 10 K to room temperature; and the heat capacities of these two crystals measured at O(200) mK demonstrate that the results are consistent with the prediction of Debye model. Consequently, a 2-cm cubic LMO bolometer is setup and running in a ground cryostat at ultra-low temperature mK-level. The energy resolution as FWHM has achieved at 7 keV@511 keV.
Speaker: Mr Deyong Duan (University of Science and Technology of China) -
243
The CROSS demonstrator: structure, performance and physics reach
Cryogenic detectors are promising instruments for investigating neutrinoless double beta decay. The CROSS project (Cryogenic Rare-event Observatory with Surface Sensitivity) aims to advance bolometric techniques using $^{100}$Mo and $^{130}$Te. The final detector, ready for commissioning at the underground Canfranc Laboratory in Spain, consists of 36 Li₂MoO₄ and 6 TeO₂ crystals, most of which will be enriched in the relevant isotope. Each crystal is coupled to a light detector to enable effective alpha background discrimination. Signal enhancement via the Neganov-Trofimov-Luke effect, combined with fast signal rise times (~0.5 ms), helps suppress background from random coincidences of two-neutrino double beta decay events.
With 4.7 kg of $^{100}$Mo and a background index of 3.2×10⁻³ counts/(keV·kg·yr), CROSS aims—after two years of data taking—to reach a $^{100}$Mo half-life sensitivity of 9.3×10²⁴ years. This would probe the effective Majorana mass down to 130–210 meV, potentially setting the most stringent global limits for this isotope.
Speaker: Dr Andrea Giuliani (CNRS/IJCLab) -
244
Calculation and comparison of sensitivities in $0\nu\beta\beta$ experiments based on key parameters
Worldwide efforts are underway to detect neutrinoless double beta ($0\nu\beta\beta$) decay using experiments based on various technologies and target isotopes. Future experiments in this regard aim to exclude the inverted order (IO) condition or explore the normal order (NO) band. Consequently, comparing the sensitivities of proposed $0\nu\beta\beta$ decay experiments with promising prospects is essential. The current study adopts sensitivity metrics, including exclusion and discovery sensitivities, half-life sensitivities, and mbb sensitivities, to provide a comprehensive evaluation of 10 typical promising experiments: LEGEND, CDEX, NEXT, nEXO, XLZD, PandaX, ,KamLAND-Zen, JUNO, SNO+, and CUPID, and highlight their unique features. Based on reported experimental parameters, the concept of a technical line is introduced to determine the location that each experiment may realize in the $\xi $ and$\lambda_{b}$ space, where $\xi$ represents the sensitive exposure per year, and $\lambda_{b}$ denotes the expected annual rate of background events. Half-life sensitivities for the selected experiments are calculated, some of them in multiple phases while others in conservative or aggressive condition. The results indicate that increasing the operation time is more benecial for zero-background experiments, which also demonstrate greater competitiveness in discovery sensitivity. mbb sensitivities are presented as uncertainty bands arising from the nuclear matrix element uncertainties. Additionally, half-life and mbb sensitivities are estimated under ideal conditions, where only background induced by $2\nu\beta\beta$ and elastic scattering of solar B-8 neutrinos remains. The upper limits of background reduction achievable with current experimental setups are also demonstrated.
Speaker: Xiao Yu (Tsinghua University)
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239
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Underground Laboratories: parallel session 6 North Hall #3
North Hall #3
Convener: Shukui Liu (Sichuan University)-
245
First Results from the CRAB Experiment at the TRIGA Mark-II Reactor
The CRAB (Calibrated nuclear Recoils for Accurate Bolometry) project is aimed at precise calibration of cryogenic detectors at sub-keV nuclear recoil energies, addressing key challenges in coherent neutrino scattering and low-mass dark matter detection.
After the successful validation of the method, demonstrated by the detection of a 112 eV recoil peak in a CaWO$_4$ cryogenic detector exposed to a commercial neutron source, an innovative experimental setup has been installed at the TRIGA Mark-II reactor at the Atominstitut in Vienna, where the cryostat is combined with a low-intensity thermal neutron beam and gamma detectors.
In this talk, we present the first commissioning results, including stable cryogenic detector operation, validation of our understanding of the external backgrounds and world’s first observation of neutron capture induced coincidences between gamma detectors and cryogenic targets. These results pave the way for a broad physics program with various target materials, including CaWO$_4$, Al$_2$O$_3$, Ge, Si.Speaker: Elisabetta Bossio (CEA Paris Saclay) -
246
Development of nuclear power plant reactor monitoring by the neutrino method using the iDREAM detector
In the 90s of the 20th century, scientists at the Kurchatov Institute experimentally proved that antineutrino spectrometers based on liquid scintillators can monitor the power of a nuclear reactor and the isotopic composition of burning fuel. These capabilities provide a complementary way of nuclear power plant reactor monitoring with respect to the standard methods in the framework of in-reactor control system. Moreover, such capability offers a promising tool for studying the dynamics of fuel burnout and changes in its isotopic composition in experimental industrial reactors of the 4th generation.
The iDREAM (industrial Detector of reactor antineutrinos for monitoring) experiment is aimed for precision spectrometry of reactor antineutrinos, studying so-called "reactor anomalies" and remote monitoring of nuclear reactors based on the characteristics of the antineutrino flux and spectrum, including for technical support of IAEA non-proliferation safeguards. In addition, since an industrial nuclear reactor is an exceptionally powerful source of gamma rays a nearby liquid scintillation detector allows us to study rare processes that go beyond the Standard Model.
The detector is a spectrometer based on liquid organic scintillator (LOS) where reactor antineutrinos are detected via inverse beta-decay reaction. The 1.1 m3 antineutrino target is filled with Gd-dopped linear alkylbenzene (LAB) based LOS. The original recipe and operational procedures ensured experimentally confirmed long term chemical stability and stability of the transparency and light yield. The detector is mounted at a distance of 19.5 m from the core center of the VVER-1000 reactor No. 3 of the Kalinin NPP with thermal power 3000 MW. The detector has been collecting data since 2022. Over several years of continuous data collection, the detector has shown a confident sensitivity to a drop in reactor power in the counting mode. Based on the data from the iDREAM neutrino detector, the daily energy output of the VVER-1000 industrial nuclear reactor was measured using the relative method. It is shown that the agreement between the results of measurements of energy output via neutrinos and data from in-reactor control systems reaches a value better than 1%.Speaker: Dr Alexander Chepurnov (Scobelcyn Institute of Nuclear Physics Moscow State University) -
247
Nuclear Recoil Tracking for Directional CEvNS Measurements
Tracking capabilities for Nuclear Recoils (NRs) from Coherent Elastic Neutrino Nucleus Scattering (CEvNS) interactions would allow for the measurement of both a NR's energy and direction. This capability would enable an expansive physics program which leverages the kinematics of the neutrino's coherent scattering interaction. This talk will discuss some of the physics applications of NR tracking for CEvNS interactions, and present simulation studies of detector configurations that leverage gaseous TPCs for NR tracking.
Speaker: David Caratelli (UC Santa Barbara) -
248
Development and test of a prototype time projection chamber for RELICS neutrino experiment
Coherent elastic neutrino-nucleus scattering (CEvNS) provides a unique channel for the detection of neutrinos. The REactor neutrino LIquid xenon Coherent Scattering experiment (RELICS) aims to detect CEvNS signals from reactor neutrinos using a 50 kg-scale liquid xenon time projection chamber (LXeTPC). To validate the principles and key technologies of RELICS experiment, we developed a 0.56-kg prototype detector equipped with 14 1-inch photomultiplier tubes (PMTs), and integrated systems for cryogenics, purification, and data acquisition. In this talk, we will present detailed test results of the prototype, and focus on single-electron readout, detector responses of Ar-37 and Kr-83m calibration sources, and background characters in the sub-keV energy region. These studies not only preliminarily verified the low-threshold detection principle of future full-scale RELICS experiment, but also provide measurements of scintillation and ionization characterizations of liquid and gaseous xenon under low-energy electronic recoil conditions.
Speaker: Lingfeng Xie (Tsinghua university) -
249
The measurement of the wavelength-dependent water transparency in Super-Kamiokande
Cherenkov photon in water is scattered or absorbed by electrons, nuclei, and some other particles. Evaluating the extent of this attenuation is necessary to accurately extract physics in the Water Cherenkov experiment. Especially, in the atmospheric neutrino and proton decay analyses (GeV-scale physics), since the Cherenkov ring becomes unclear due to photon scattering, it affects the accuracy of Cherenkov ring counting and particle identification. On the other hand, in the solar neutrino and reactor neutrino analyses (MeV-scale physics), since the energy is determined by the number of photon hits at PMTs, it affects the accuracy of the energy. In addition, since 2020, Gadolinium was dissolved into pure water in the Super-K tank. Thanks to it, event identification using neutron capture in Gd was enhanced. Since the neutron capture signal is 8 MeV, it is important to correctly evaluate the photon attenuation in this case as well. Therefore, Super-K uses optical lasers with different wavelengths to measure the water transparency for each wavelength and introduces it into the MC simulations as wavelength functions. Recent years, we have done the first measurement using Geant4 based MC simulation. In this presentation, we will report the results of the wavelength-dependent water transparency conducted since 2019 and comparisons between Grant4 based MC and conventional GEANT3 based MC, and before and after Gd dissolving.
Speaker: Tomoaki Tada (Okayama University, Japan) -
250
New 1-ton neutrino detector at CJPL-I: equipment upgrades and performance
Our research at the China Jinping Underground Laboratory (CJPL) has produced significant results from various phases of the 1-ton liquid scintillator neutrino detector. As part of the preliminary phase of the Jinping Neutrino Experiment (JNE), we have investigated its performance at CJPL-I. In 2023, we initiated an upgrade to the 1-ton detector, which primarily involves integrating self-developed electronic systems and 60 MCP-PMTs that we plan to incorporate into JNE. Following this upgrade, the 1-ton detector underwent a series of meticulous tests: first, a Dry-run test phase; next, a pure water operation phase; and finally, a liquid scintillator operation phase. These stages have yielded numerous research outcomes. In this conference, we will present our latest achievements regarding the 1-ton detector in several key areas: evaluations of performance and stability for both MCP-PMTs and self-developed electronic systems and assessments of operational performance during pure water and liquid scintillator phases.
Speaker: Haozhe Sun (Tsinghua University) -
251
Modelling of HPGe Detectors for the LEGEND Experiment and Low-Background Research
The LEGEND experiment is a phased programme designed to search for neutrino-less double beta decay with unprecedented sensitivity, targeting a half-life of up to 10^28 years, corresponding to a Majorana neutrino mass range of 9–21 meV. Its first phase, LEGEND-200, is currently taking data at the Gran Sasso Underground Laboratory and aims to reach a sensitivity of 10^27 years (28–66 meV).
LEGEND employs high-purity germanium (HPGe) detectors enriched in 76Ge, operated in liquid argon. Accurate modelling of the detector response and background contributions is essential for maximising discovery potential and informing detector design and analysis strategies. In this talk, we describe a Geant4-based simulation framework developed for LEGEND, including geometry modelling, signal generation, charge transport, and detector response. We also introduce the validation of the simulation framework and its application for LEGEND background modelling and material screening in ultra-low background experiments.
Speaker: Difei Xu
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245
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Poster session International Conference Center
International Conference Center
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252
A Likelihood-Based Framework for CEvNS Analysis Using Reactor Rate Modulation
Coherent elastic neutrino-nucleus scattering (CE$\nu$NS) experiments at research reactors benefit from regular reactor off-periods, allowing for effective background subtraction. At commercial reactor facilities, off-periods are rare and short due to the priority of continuous energy production. In facilities with two or more reactors, temporary shutdowns for maintenance naturally introduce time-varying neutrino fluxes - enabling reactor rate modulation analysis.
A key advantage of a pure rate-based analysis is its independence from background modeling, under the condition of a background constant in time - a powerful feature for robust and unambiguous CE$\nu$NS discovery.
We present a dedicated framework designed to perform CE$\nu$NS analyses by incorporating time-dependent reactor power profiles into the likelihood. The framework includes flexible signal and background models defined in energy, time, or both, enabling rate-only, shape-only, or combined analyses using either binned or unbinned likelihoods. It also provides tools to generate pseudo-experiments for sensitivity studies and robust frequentist statistical inference.
Originally developed with the NUCLEUS experiment in mind, the framework is broadly applicable to any CE$\nu$NS experiment operating under time-dependent reactor conditions. We will show how different systematic uncertainties, such as energy scale and background model, impact the various analysis strategies, providing guidance for experimental design and optimization to maximize discovery potential.Speaker: Elisabetta Bossio (CEA Paris Saclay) -
253
A new tellurium-loaded liquid scintillator based on water and p-dioxane
Tellurium-loaded liquid scintillators are critical for neutrinoless double-beta decay experiments, but conventional formulations face limitations in tellurium loading due to solubility and chemical compatibility issues. In this work, we develop a novel surfactant-free, water-compatible liquid scintillator based on p-dioxane, incorporating telluric acid, water, and naphthalene, with PPO as the fluor. A ternary solubility phase diagram of the tellurium–water–p-dioxane system was established, enabling the identification of stable compositions that accommodate both desired tellurium content and scintillation performance. Efficient energy transfer from solvent to fluor was achieved through the intermediate role of naphthalene, and the optimized formulation exhibited light yield comparable to conventional organic scintillators. Despite quenching effects introduced by water and telluric acid, these results demonstrate the feasibility of surfactant-free, water-compatible tellurium-loaded scintillators. This work serves as a proof of concept for a new design framework toward high-loading liquid scintillators.
Speaker: Ye Liang (Tsinghua University) -
254
A research of proto-neutron star evolution and the structure near the surface
A proto-neutron star (PNS) is born after a core-collapse supernova. The size of the young neutron star exceeds that of a typical neutron star and consists of dense, hot nuclear matter. In discussions of PNS evolution, neutrinos play a crucial role. It is generally understood that the emission of neutrinos leads to the cooling of the PNS. With upcoming neutrino detectors such as upgraded water-Cherenkov observatories and the liquid scintillator detector JUNO in China, the observable duration is expected to extend to several tens of seconds during a Galactic supernova event.
To investigate the long-term evolution of the PNS, we employed a quasi-static evolution code that solves neutrino transport using a multi-group flux-limited diffusion scheme under spherical symmetry with general relativity. We computed the evolution up to 50 seconds for two different nuclear equations of state (EOS). Additionally, we discuss the thermal structure near the surface where the crust is expected to form.
Since convective motions within the PNS are expected to significantly affect its evolution, we implemented a diffusion-based treatment of convection in our code. Partial evolution results incorporating this convective module are also included for comparison with earlier models.
Speaker: Jinkun Liao (Tokyo University of Science) -
255
Advancing Muon Veto Systems for the Future ANDES Underground Laboratory
Muon veto detectors are crucial for deep underground experiments, designed to filter out cosmic muons that can mimic rare physics signals. Despite significant overburden, residual muons penetrate facilities like the future ANDES Laboratory, necessitating effective veto systems for low-background environments.
Our scientific groups are actively developing innovative muon detector designs and new sensor technology. We have designed and already constructed two muon telescopes for deployment in mines near ANDES, both in Argentina and Chile, to precisely measure muon flux and arrival directions. These measurements are vital for modeling and mitigating muon backgrounds, optimizing shielding, and validating simulation tools essential for experiment design and site selection.
A key advancement in our sensor, currently under development, is a novel digital Silicon Photomultiplier (dSiPM). This new device is specifically engineered to detect the faint light produced by scintillating fibers, which are commonly used in large muon detectors. It combines an array of Single-Photon Avalanche Diodes (SPADs) with on-chip CMOS circuitry for signal processing, enabling time-stamping and positional information at the individual SPAD level. These features will significantly enhance the capabilities of future muon veto systems.
Please revise and supplement the content.Speakers: Dr Alberto Etchegoyen (ITeDA(CNEA,CONICET,UNSAM)), Prof. Manuel Platino (ITeDA(CNEA,CONICET,UNSAM)) -
256
An interpretation involving ALPs in the TeV spectrum of GRB 221009A
The extraordinary gamma-ray burst (GRB) 221009A, identified as the brightest GRB ever recorded, exhibited remarkable high-energy emissions as observed by the Large High Altitude Air Shower Observatory (LHAASO). We demonstrate that synchrotron self-Compton (SSC) emission from shock-accelerated electrons during the afterglow phase can account for the observed spectral energy distribution (SED) of GRB 221009A in the GeV–TeV range. However, the portion of the SED above 8 TeV is difficult to interpret due to severe attenuation by extragalactic background light (EBL). To address this issue, we consider the role of axion-like particles (ALPs), which can convert into photons and vice versa in the presence of magnetic fields during propagation. We apply the Markov Chain Monte Carlo (MCMC) method to fit the observed spectrum using the SSC model while accounting for EBL absorption. For photons above 8 TeV, we employ the CLs method to explore exclusion regions in the ALP parameter space by comparison with the EBL absorption model. Our results show that ALP-photon conversion can effectively explain the observed TeV spectrum, particularly above 8 TeV, and suggest that GRB 221009A can provide competitive constraints on ALP parameters space.
Speaker: P. H. Thomas Tam (Sun Yat-sen University) -
257
AXEL Experiment: Research and Development of a Novel Xenon Gas Scintillation Detector
A Xenon ElectroLuminescence (AXEL) experiment aims to search for neutrinoless double beta decay ($0\nu2\beta$) using a high-pressure xenon gas Time Projection Chamber (TPC).
The AXEL 180 L prototype detector, developed to demonstrate the feasibility of $0\nu2\beta$ search, determines the event start time—essential for reconstructing the z-position of ionization electron production—by directly detecting scintillation light using a VUV-sensitive photomultiplier tube.
However, the current scintillation light yield is insufficient, resulting in z-misreconstruction and, consequently, degradation of energy resolution.
To realize the world’s highest sensitivity in a future ton-scale TPC for $0\nu2\beta$ search, a significant improvement in scintillation light collection is required to improve the energy resolution.
Currently, we are developing a novel scintillation detector that combines an expanded light collection area with wavelength shifting and photon trapping techniques. This detector is currently undergoing active performance evaluation.
In this poster, we present an overview of a novel scintillation detector concept and preliminary results from performance tests in high-pressure xenon gas.Speaker: Soki Urano (Tohoku University) -
258
AXEL: development of a high-voltage distribution system and low-mass field cage for construction of a next large detector
A Xenon ElectroLuminescence (AXEL) experiment, which is aimed at detecting neutrinoless double beta decay (0$\nu\beta\beta$) with a high-pressure xenon gas time projection chamber, is on progress. Construction of a 1000L-size detector for a demonstration of AXEL detector performance is currently underway, and some new technologies are needed to operate this large-size detector. Our detector employs a modular structure for ionization electron detection, allowing for scalability by adding additional modules. However, the attached anode electrode consists of a single copper plate covering all of the modules now. For larger detectors, it is preferable to supply high voltage to each module independently to minimize power of a discharge and risk of detector failure due to part of low discharge endurance. So, a novel distribution system, which can supply and adjust high voltage module by module is being developed. Another subject is about the field cage. Since reduction of background contamination is essential for searching 0$\nu\beta\beta$, we are developing a field cage made of flexible print circuits with a structure that prevent discharges between electrodes and charging-up on the surface. These techniques allow AXEL detector to have large mass of double beta decay nuclei and then become the world’s most sensitive experiment on 0$\nu\beta\beta$ search.
Speaker: Hayato SASAKI (Kyoto University) -
259
Background Modeling of AMoRE-I
AMoRE is an international collaboration to search for the neutrinoless double-beta (0νββ) decay of ¹⁰⁰Mo, utilizing enriched molybdate scintillating crystals. AMoRE-I, the second phase of the program following the AMoRE-Pilot, was conducted at the Yangyang Underground Laboratory(Y2L) over a period of 29 months (December 2020 – May 2023), using an array of 18 crystals with a total mass of 6.194 kg.
We present a report on the background study of the AMoRE-I experimental data with 8.02 kg·year exposure. The model includes contributions from major background sources. Internal sources such as ²³²Th, ²³⁵U, ²³⁸U, ⁴⁰K, and two-neutrino double-beta decay (2νββ) of ¹⁰⁰Mo, along with external components including gamma rays from ²²²Rn daughters, neutrons, and radiation from surrounding rocks, are simulated using Geant4. We compare the experimentally measured beta-gamma spectrum to the results from Monte Carlo simulations.Speaker: Mr B. Bhandari (Sejong University) -
260
Background rejection by Pulse Shape Discrimination in the LEGEND experiment
The LEGEND (Large Enriched Germanium Detector for Neutrinoless $\beta\beta$ Decay) collaboration aims to detect neutrinoless double-beta (0$\nu\beta\beta$) decay in $^{76}$Ge using enriched high-purity germanium (HPGe) detectors. In its first phase, LEGEND-200 successfully acquired physics data for over a year using 140 kg of HPGe detectors deployed in a liquid argon cryostat. LEGEND-200 has a background goal of less than $2 \times 10^{-4}$ cts/(keV kg yr). This requires excellent background mitigation capabilities, both passive and active.
The sources of background (contributing in the region of interest) include the alphas and betas originating from the detector surface and gamma rays that undergo Compton scattering in the detector bulk. In contrast, 0$\nu\beta\beta$ events are expected to be bulk, single-site events.
Pulse Shape Discrimination (PSD) is a powerful set of techniques used by LEGEND-200 to reject event populations with background-like topologies, using information from the shapes of signals produced by HPGe detectors. PSD techniques take advantage of the properties of point-contact detector geometries used by the experiment.
The poster will describe the techniques developed for the different detector geometries in LEGEND and how to evaluate the signal acceptance efficiency and systematics at the 0$\nu\beta\beta$ energy.Speaker: Raoul Cesarano (Gran Sasso Science Institute (GSSI)) -
261
Calibration of 20-inch Photomultiplier Tubes in JUNO
The Jiangmen Underground Neutrino Observatory (JUNO) is the world’s largest liquid scintillator detector, utilizing 20 kton liquid scintillator as target mass, and equipped with 17,612 20-inch and 25,600 3-inch photomultiplier tubes (PMTs) in its central detector for photon detection. There are two types of 20-inch PMTs in JUNO, including the MCP-PMT manufactured by Northern Night Vision Technology Co. (NNVT), and the dynode PMT manufactured by Hamamatsu Photonics K.K. (HPK). JUNO’s primary objective is to determine the neutrino mass ordering by precisely measuring the reactor anti-neutrino energy spectrum. To achieve this goal, it requires an energy resolution better than 3% at 1 MeV, and an energy scale uncertainty less than 1%. A precise calibration of the gain and single photoelectron charge spectrum is a prerequisite for both waveform and energy reconstruction, and is therefore of fundamental importance. This poster presents the calibration strategy, data analysis method and calibration results for the 20-inch PMTs in JUNO.
Speaker: Yaoguang Wang (Shandong University) -
262
Calibration system of the JUNO experiment
The Jiangmen Underground Neutrino Observatory (JUNO) is the world's largest liquid scintillator detector, located in Jiangmen, South China. Its construction has been completed, and it is currently undergoing liquid scintillator filling. The central detector consists of an acrylic spherical vessel with an inner diameter of 35.4 m, filled with 20 kton of liquid scintillator. It is equipped with 17,612 20-inch and 25,600 3-inch photomultiplier tubes (PMTs) to collect photon signals. JUNO is a multi-purpose experiment designed to determine the neutrino mass ordering, precisely measure neutrino oscillation parameters, and detect neutrinos from both celestial and terrestrial sources, etc. To achieve an energy resolution better than 3% at 1MeV and an energy scale accuracy better than 1%, a comprehensive calibration system has been developed. This system can deploy multiple radioactive and laser sources at various positions inside and around the detector. Furthermore, the calibration strategy has been optimized based on Monte Carlo simulations. This poster will present the design and calibration strategy of the JUNO calibration system, along with its installation status.
Speaker: Rui Li (Shanghai Jiao Tong University) -
263
Can KM3-230213A be dark matter?
We explore for the first time the possibility that the recently detected ultra-high-energy neutrino event with an energy of 220 PeV, observed by the KM3NeT experiment, originates from the decay of heavy dark matter (DM). As a representative example, we consider a scenario where the DM is a heavy right-handed neutrino (RHN). We demonstrate that a DM mass of 440 PeV can account for the observed neutrino flux. The DM lifetime required to match the best-fit flux value approaches the current constraints from gamma-ray observations. Given the large uncertainty in the flux measurement, the KM3NeT event can be explained by RHN DM decay at the 3 $\sigma$ confidence level, while remaining consistent with gamma-ray limits and the absence of similar detections by IceCube.
Speaker: Prantik Sarmah (Institute of High Energy Physics Beijing) -
264
CDEX-300$\nu$ background simulation
Neutrinoless double beta decay ($0\nu\beta\beta$) represents a crucial probe of new physics beyond the Standard Mode. The technology utilizing enriched germanium detectors demonstrates unique advantages in this field due to its high isotopic enrichment, ultra-low background characteristics, superior energy resolution, and scalable configuration. The CDEX Collaboration is preparing to construct the next-generation CDEX-300$\nu$ experiment with a 225 kg-scale germanium detector array. This project will implement a liquid argon veto detector system to further suppress background, anticipating a background level reduction to $10^{-4}$ counts/(keV·kg·year). The experiment is projected to reach the $10^{27}$ year sensitivity level for $0\nu\beta\beta$ half-life within three years of operation.
To ensure the achievement of experimental goals, comprehensive background simulation studies are essential. This project aims to leverage CDEX Collaboration's expertise in low-background experiments by conducting Monte Carlo simulations of all potential background sources in the CDEX-300$\nu$ setup. Simultaneously, the veto efficiency of the liquid argon detector system will be simulated. The objectives include generating the anticipated energy spectrum of CDEX-300$\nu$, evaluating the final projected sensitivity, and providing strategic recommendations for future experimental configuration optimization.Speaker: Junzheng Wang -
265
CERES: Cryogenic Experiment to Reconstruct Energy Systematics in TeO2 bolometers
The Cryogenic Underground Observatory for Rare Events (CUORE) is an experiment searching for neutrinoless double beta decay in a ton-scale detector, located at the Gran Sasso National Laboratory in Italy. Utilizing a detector composed of $TeO_2$ crystals, CUORE operates at millikelvin temperatures to achieve sensitive measurements of temperature fluctuations from deposited energy.
A precise understanding of the energy systematics is vital for bolometric experiments. Recent studies of event topologies and energy resolution have indicated potential position-dependent effects in CUORE bolometers. In this poster, we present the design and latest results of a single-crystal experiment, CERES, to further investigate these phenomena.
*This work is supported by the US DOE Office of Nuclear Physics, the US NSF, and internal investments at all institutions.
Speaker: Tong Zhu (UC Berkeley) -
266
Characterization of Liquid Scintillator at Cryogenic Temperatures
We present a characterization of LAB-based liquid scintillator at cryogenic temperatures using a table-top setup. Measurements of relative transparency, light yield, and viscosity were performed down to approximately −100 °C. The results are discussed in the context of potential applications for the veto system in PandaX-xT, a next-generation multi-ten-ton liquid xenon experiment searching for dark matter and neutrinoless double-beta decay.
Speakers: 东齐 杨 (Shanghai Jiao Tong University), 予乐 黄 (Shanghai Jiao Tong University), 培源 李 (Shanghai Jiao Tong University), 志远 李 (Zhong Shan University), 玄烨 傅 (Shanghai Jiao Tong University) -
267
Cherenkov light separation in organic liquid scintillator for neutrino detection
Organic liquid scintillator are one of the most exploited detection medium for neutrino detection in the past years, especially for low energy ($\sim$ MeV). Although these media have a very good light yield, allowing to perform a good energy spectroscopy of the incoming particle, organic liquid scintillator lost the information of the particle direction due to the isotropy of the scintillation light.
To overcome this limitation, in the past years a huge effort by the liquid scintillator community has been started trying to combine liquid scintillator with Cherenkov detectors. In particular, Cherenkov radiation is emitted when a charged particle have a speed higher then the light speed in the medium. This radiation is usually emitted in neutrino-electron elastic scattering at the MeV energies due to the high refractive index of these media ($\sim$ 1.5), but it is overcame by the scintillation light which usually is a factor 100 more. The mixing of this two techniques will be the next step forward in neutrino dection, in particular for neutrino pointing and for $0\nu\beta\beta$ decay search, which can profit by exploiting the direction of the interaction to increase the signal over background ratio.
In this poster, I will first introduce the Milano Liquid Scintillator facility, called SHELDON (Separation of cHErenkov Light for Directionality Of Neutrinos), developed to fully characterize standard liquid scintillators but also novel liquids, like water based liquid scintillator (WbLS) or slow liquid scintillator (SLS). I will focus more the high resolution ($\sim 0.4$ ns) time profile apparatus devoted to measure fluorescence and Cherenkov time profiles. Then I will present the optical separation technique which allow to enhance the Cherenkov contribution by exploiting bandpass filters, that could be exploit by next generation neutrino experiments.Speaker: Marco Beretta (INFN - University of Milano) -
268
Combined search for cosmic neutrino sources with ANTARES and KM3NeT/ARCA
The search for cosmic neutrino sources is a major objective of high-energy astrophysics. The ANTARES neutrino telescope, operational from 2007 to 2022 in the Mediterranean Sea, provided valuable data over 16 years, achieving an angular resolution better than 0.4° at the highest energies and offering a privileged view of the Southern sky. Following its legacy, the KM3NeT/ARCA detector is currently under construction near the coast of Southern Italy. Upon completion, ARCA will instrument a volume of about one cubic kilometer and achieve an angular resolution below 0.1° for muon neutrinos above 300 TeV. Currently, more than 10% of the detector is installed and collecting data.
This work presents a combined analysis based on the full ANTARES dataset and KM3NeT/ARCA data recorded between May 2021 and September 2023, with an evolving detector geometry up to 21 detection lines. Searches for neutrino emissions from both point-like and extended sources are performed, using a comprehensive catalogue of gamma-ray emitters, including Galactic sources (from TeVCat), extragalactic AGNs detected by VLBI, and candidates previously highlighted by IceCube.
The combination of ANTARES and ARCA data improves the sensitivity over a wide energy range, from few TeVs to several PeVs, with a particular advantage in the Southern sky. The results of this analysis contribute to ongoing efforts to identify the origin of cosmic neutrinos within the framework of multi-messenger astrophysics.Speaker: Vittorio Parisi (INFN Genova, University of Genova) -
269
Core-Collapse Supernova monitor study during the JUNO filling phase
The Jiangmen Underground Neutrino Observatory (JUNO) is a 20-kiloton liquid scintillator detector with the capability to detect neutrinos from the next Core-Collapse Supernova (CCSN) and effectively manage the resulting large statistics. The real-time CCSN monitoring system of JUNO is designed to provide fast and reliable alerts by tracking the increasing event rates of supernova burst neutrinos and pre-supernova neutrinos. Upon detecting an alert, the system will record as much data as possible for rapid analysis, facilitating multi-messenger observations of CCSN events. The CCSN monitoring system comprises both prompt monitors and online monitors, ensuring swift alert generation while maintaining comprehensive coverage of progenitor stars. This poster will discuss the implementation and extensive testing of the CCSN monitoring system conducted during the JUNO filling phase.
Speaker: YIXUAN JIANG (The Institute of High Energy Physics of the Chinese Academy of Sciences) -
270
Cosmic-ray sun shadow observation beyond TeV with LHAASO
The cosmic rays blocked by the Sun can create a deficit shadow when observed with ground-based observatories. This Sun shadow serves as a valuable tool for capturing the complete magnetic field information of solar activities, as well as the magnetic field information between the Sun and the Earth.
In this study, we will present observations of the Sun shadow using the Large High Altitude Air Shower Observatory (LHAASO) across an energy range from sub-TeV to PeV. We will analyze key observational characteristics of the Sun shadow, such as the deficit cosmic-ray event ratio, shadow extension, and energy-dependent morphology. Additionally, we will discuss the time variation of the deficit ratio with Sunspot activity, potential studies on the coronal magnetic field (CMF), and interplanetary magnetic field (IMF), which may be closely related to the puzzling high-energy gamma radiation observed from the Sun.Speaker: Houdi Xing (中国科学院高能物理研究所(IHEP)) -
271
Design and Development of an Electron Lifetime Monitor for Future Noble Element Experiments
Noble liquid time projection chambers (TPCs) are essential detector technologies in dark matter searches and neutrino experiments. A key performance parameter for these detectors, whether using liquid argon or liquid xenon, is the electron lifetime. This work presents a low-noise, high-precision electron purity monitoring system developed for such applications. The system comprises two main components: a drift chamber and a charge amplifier, carefully designed to minimize electric field leakage and reduce systematic uncertainties. The electron source can be either laser-generated photoelectrons or emissions from radioactive sources. Experimental results show that the amplifier achieves a gain of -333.33 mV/pC with a noise level below 1 mV. The system maintains excellent linearity across an input charge range from 6 femtocoulombs (fC) to 6 picocoulombs (pC). It enables continuous, real-time monitoring of electron lifetime, particularly valuable during purification. Sharing a single amplifier for both signal collection and readout eliminates the need for separate calibration and further reduces systematic errors. This poster will present the system schematic and report the current status of measurements.
Speaker: GaoShuang Li (IHEP,CAS) -
272
Design and preliminary Test Results of a prototype LAr veto System for the CDEX-300 0νββ Experiment
The CDEX-300 is a next generation neutrinoless double beta (0νββ) decay experiment aiming at searching the 0νββ decay of Ge-76 using high purity germanium (HPGe) detectors. One key technology for background suppression in CDEX-300 is the liquid argon (LAr) veto, and the smooth operation and impurity control of the LAr are important for veto performance in the long-term operation. We built a liquid argon prototype system as a test facility for studying the impurity control and veto performance of LAr in the surface building of China Jinping Underground Laboratory. Here we report the design of the system and preliminary test results.
Speaker: Yisen Lan -
273
Design of RFSoC Based Hardware Module for Electronics System of Frontier Physics Experiments.
The high-speed integrated data converters and digital data processing capability in RFSoC empower direct RF sampling without analog mixer up and down conversion for RF frequencies up to 5 GHz with more compact footprint and lower total power consumption and cost. This work reports the hardware design methodology of RFSoC, the power sub-system which include 80-A 0.85V core supply with dual phase DC-DC in used and 72-Bit DDR4 SDRAM is implemented for PS sub-system. At the same time, dual 16-Bit DDR4 SDRAM is designed for PL sub-system. For the footprint optimization, dual side mounted (Top and Bottom) DDR4 chips topology is used and capacitive-compensation signal integrated method is used. 8-Channel 5 GSps/14-Bit ADC and 8-Channel 9.85 GSps/14-Bit DAC high-speed analog differential signals are fan-out with Samtec ADM/ADF high-speed and high-density connectors. While the 8-Channel 25 G-bit GTY transceivers are all fan-out with the same connectors. The compact size of this module is 70mm plus 96mm and which is suitable for readout and control system with state-of-the-art microwave SQUID multiplexers, and also capable for the digitalization of MCP PMT with 200-ps rising time.
Speaker: Mr Liangjun Wei (Tsinghua University) -
274
Developing a supernova neutrino burst trigger at DUNE
The Deep Underground Neutrino Experiment (DUNE) is a liquid argon neutrino detector currently under construction in the United States. One key physics goal of the experiment is to observe the neutrino signal from a core-collapse supernova in our galactic neighbourhood. DUNE’s LAr-TPC design will provide unique sensitivity to the electron neutrino component of a supernova burst neutrino signal via charged current interactions. This signal has many unique features compared to that of other neutrino sources and can provide significant challenges to the data acquisition (DAQ) system. Burst detection relies on the development of a dedicated supernova burst trigger for DUNE, with the aim of providing prompt and reliable early warnings for astronomers in the event of a supernova in our galaxy. Expected supernova sensitivities and background rates for the DUNE Far Detector will be presented.
Speaker: Sophie Butchart (University of Sussex) -
275
Development and characterization of the JNE concentrator
The Jinping Neutrino Experiment (JNE) plans to deploy approximately 3000 8-inch MCP-PMTs (GDB-6082, North Night Vision Technology) for neutrino detection. To improve photon collection efficiency while maintaining cost-effectiveness, we developed custom-designed light concentrators with a selected cutoff angle of $70^\circ$, mounted on each PMT.
We performed angular response measurements of the concentration factor at four wavelengths in air. The results are in good agreement with Monte Carlo simulations, validating the optical performance of the design. Under parallel light source, the concentrators enhance light collection efficiency by approximately 40%, with a marginal increase in transit-time spread (FWHM increase < 0.3 ns).
These findings demonstrate that the proposed concentrator design is effective and practical for use in JNE, offering significant photon collection enhancement with minimal timing degradation.
Speaker: Shuai Ouyang (Shandong University) -
276
Development of a Multi-Purpose Optical TPC for Neutron-Induced Reaction Studies at SARAF
Neutron-induced reactions play a central role in stellar and Big Bang nucleosynthesis. Yet many of the relevant cross sections remain poorly constrained at astrophysically relevant energies. Addressing this need, we are developing a multi-purpose Optical Time Projection Chamber (OTPC) optimized for precision neutron-reaction studies at SARAF’s upcoming high-intensity, time-of-flight neutron beam facility.
The detector combines a drift chamber filled with CF₄-based scintillating gas mixtures, fast photodetectors for prompt scintillation (S1) detection, and high-speed optical readout of avalanche-induced secondary scintillation (S2) to enable full 3D reconstruction of charged-particle tracks.
A prototype system has been assembled and tested. This has enabled systematic characterization of drift velocity, charge and light amplification, and initial optical imaging of alpha-particle tracks in various gas mixtures.
These studies guide the design of a larger, fully integrated OTPC system intended for operation at SARAF.
In parallel, we are exploring advanced image sensors to further enhance tracking resolution. We report on recent progress with the prototype and outline the next steps toward commissioning the full system.Speaker: Dr Ryan Felkai (Weizmann Institute of Science) -
277
Development of a spring-mass vibration damping system for a Jinping bolometric demonstrator experiment
To achieve ultra-low noise level and high energy resolution in rare event searches, bolometric detectors require an extremely low-vibration working environment. In this study, we present the design, implementation, and performance evaluation of a spring-mass vibration damping system developed for a bolometric demonstrator experiment for neutrinoless double beta decay (0vββ) search at the China Jinping Underground Laboratory (CJPL). Mechanical noises from the experimental setup, particularly those from the pulse tube cryocoolers of the cryogenic system, are measured. The performance of the spring-based vibration damping system is studied in a laboratory environment, with a focus on the 0–100 Hz low-frequency range, which significantly impacts data acquisition of the 0vββ experiment. Insights for the system improvements for the future experiments are also discussed.
Speaker: Huaqi Cao (FuDan University) -
278
Development of Neutron Transmutation Doped Ge (NTD-Ge) sensors for cryogenic bolometers
NTD-Ge (Neutron Transmutation Doped Germanium) is one of the crucial components in bolometer systems, boasting a large dynamic response range and high sensitivity. A group of 10N HPGe samples are irradiated by thermal neutrons with different flux at China Advanced Research Reactor. After a half-year cooling down, these samples are fabricated into NTD-Ge sensors hiring the developed technological processes, following as defect characterization evaluation, thermal annealing, surface treatment and point/wrapped around electrode coating, and etc. In addition, a mK cryogenic testing platform is established to study the low-temperature properties of NTD-Ge for the applications in bolometers.
Speaker: Mr Deyong Duan (University of Science and Technology of China) -
279
Development of Real-Time Pulse Processing IP Based on FPGA
With the increasing demands on particle detector signal processing in fields such as high-energy physics, traditional analog or digital solutions struggle to balance performance and flexibility. To address this, this paper develops an FPGA-based real-time signal processing program for particle detectors. The program integrates algorithm modules including signal shaping, pulse triggering, waveform acquisition, zero-cross timing, and pulse amplitude analysis, fulfilling most functional requirements for real-time detector signal processing. Performance-wise, the program suppresses common-mode noise through signal shaping, enhances timing accuracy via linear interpolation, and prevents amplitude distortion through dynamic baseline scanning. Developed using Xilinx's Vivado design suite, the program features flexibly adjustable parameters for each module and unified interface protocols, enabling rapid configuration for diverse application scenarios.Experiments utilized a signal generator to produce gamma waves for functional verification after programming the data acquisition circuit. Results demonstrate: The shaping module effectively eliminates signal common-mode baseline drift; The triggering module achieves accurate triggering without false positives at thresholds as low as 0.3% of the full scale; The timing module delivers high-precision timing measurements; The pulse amplitude analysis module attains high resolution (0.026%@200 mV) while maintaining excellent linearity in pulse amplitude spectra. These outcomes provide a novel solution for online real-time processing of particle detector signals.
Speaker: Binkai Qi -
280
Diagnosing the origin of dense circumstellar material in a multi-energy neutrino astronomical approach
We propose a novel approach to investigate the mysterious origin of enhanced circumstellar material (CSM) surrounding a collapsing massive star using neutrinos. Here, non-thermal TeV neutrinos produced from ejecta–CSM interactions and thermal MeV neutrinos from a pre-explosion burning process are related under the assumption that CSM had been created through the pre-supernova neutrino release. Our idea initiates astrophysical studies utilizing neutrinos from multiple energy regimes. In this presentation, we show the calculated spectrum and light curve of high-energy neutrinos derived from a representative pre-supernova model as well as the detected event rates along time at JUNO and IceCube. In addition, we discuss the application range of the proposed method.
Speaker: Yosuke Ashida (Tohoku University) -
281
EBL study with HAWC observations of high-emission states of Mrk 421
Emission of TeV gamma rays from high-emission states of nearby Active Galactic Nuclei (AGNs) can be used to put constraints on the photon density of the Extragalactic Background Light (EBL) in a region where there are not direct measurements of this background radiation field. Using HAWC observations of the AGN Mrk 421 after 10 years of data, we show preliminary evidence of the existence of two different emission states and their associated spectrum. Additionally, we show preparatory constraints on the EBL photon intensity around 1 TeV.
Speaker: Ramiro Torres Escobedo (上海交通大学) -
282
Energy calibration of the BULLKID-DM experiment
BULLKID is a monolithic array of dice of 5.4 x 5.4 x 5.0 mm3 carved in a silicon crystal and sensed by phonon-mediated cryogenic Kinetic Inductance Detectors (KIDs). It is designed for the detection of sub-keV energy depositions from particle interactions within the crystal, making it suitable for direct Dark-Matter (DM) searches and coherent elastic neutrino-nucleus scattering (CE𝜈NS) experiments.
One of the main challenges in this low-energy regime is the energy calibration, which is typically performed through the emission lines of radioactive sources in the O(keV) range followed by the linear extrapolation of the detector response down to threshold.
To overcome this limitation, the BULLKID-DM collaboration employs a method based on bursts of UV-Vis photons, that allows the individual calibration of the dice. This technique enables individual calibration of the KIDs in the array and allows for controlled signal generation across an energy range from a few eV up to tens of keV enabling a wide range detector characterization. However, photons produce electron recoils near the surface of the crystal, unlike DM or CE𝜈NS interactions, which produce nuclear recoils uniformly distributed throughout the crystal volume (bulk events).
Validating this optical calibration method, using particle interactions, is thus of critical importance. We performed two measurements: one of the 59.5 keV gamma rays of a 241Am radioactive source and another using X-rays from lead facing the detector. The optical calibration is validated within a 10% deficit with respect to the true energy and we find no hint of different detector response with the depth of the interaction in the crystal.
Finally we present an ongoing study of a calibration method based on the response function of the detector which may be employed in absence of external sources during the data taking.
Speaker: Matteo Folcarelli (Sapienza University of Rome) -
283
Extending the sensitivity of heavy sterile neutrino searches with solar neutrino experiments
A sensitivity study of the search for heavy sterile neutrinos ($\nu_H$) in the MeV mass range using solar neutrino experiments is presented. $\nu_H$ with masses ranging from a few MeV up to 15 MeV can be produced in the Sun through $^8\mathrm{B}$ decay and subsequently decay into $\nu_L + e^+ + e^-$, where its flux and lifetime strongly depend on the mixing parameter $|U_{eH}|^2$ and mass $m_{\nu_H}$. The $\nu_H$ signal can be detected via its decay products—either the $e^+ + e^-$ pair or $\nu_L$—depending on whether $\nu_H$ decays inside or outside the detector. Expected signal yields for both detection methods are presented across the full $|U_{eH}|^2$ and $m_{\nu_H}$ parameter space. These two methods are found to be complementary in different regions of the $|U_{eH}|^2$ and $m_{\nu_H}$ phase space. By combining both approaches, we anticipate observing at least a handful of signal events in nearly all regions of the parameter space of $10^{-6} < |U_{eH}|^2 < 1$ and $2~\mathrm{MeV} < m_{\nu_H} < 14~\mathrm{MeV}$, assuming a 500-ton solar neutrino experiment operating for one year. Key discriminative variables—such as the energy spectra of $\nu_L$ or $e^+ + e^-$, as well as the $\nu_L$ solar angle—are also presented to aid in the rejection of major backgrounds such as solar neutrino events.
Speaker: Yutao Zhu (Tsinghua University) -
284
First Measurement of High-Energy Neutron-Induced γ-Rays with a Low Background GAGG Neutron Detector
A precise measurement of neutron flux is crucial for underground experiments, as neutrons may cause significant background for rare events searches. Due to the high neutron capture cross-section of the gadolinium isotopes present in the Gd$_{3}$Al$_{2}$Ga$_3$O$_{12}$ (GAGG) crystal, combined with the high attenuation coefficient for efficient detection of neutron-induced $\gamma$ rays, the GAGG scintillating crystal has the potential to show a clean signature for detecting neutrons. Furthermore, it features an excellent property of pulse shape discrimination that allows to distinguish signal-like events and backgrounds.
A prototype neutron detector has been assembled using a 100$\,$cm$^{3}$ GAGG crystal coupled to a photomultiplier tube. It is operated in the Gran Sasso underground laboratory, aiming to detect high energy $\gamma$ rays as the signal signature. This work presents the detector characterizations, regarding its performance and capabilities for particle identification, as well as intrinsic background. The neutron response measured underground will also be shown. In order to verify and optimize the setup, Monte Carlo simulations are performed, and the preliminary results will be discussed.Speaker: Yingjie Chu -
285
Gd-PMMA: a novel neutron tagging technology for low background detectors.
Low-background detectors, such as those used in direct dark matter searches, require high-efficient neutron veto systems to suppress nuclear recoil backgrounds. Gadolinium-doped polymethyl methacrylate (Gd-PMMA) has emerged as a promising solid-state neutron tagging material, combining high hydrogen content for neutron moderation with gadolinium’s strong thermal neutron capture cross-section, followed by the emission of high-energy gamma rays. These gammas can be effectively detected by both the surrounding veto buffer of the detector, e.g. liquid argon or liquid xenon. A novel Gd-PMMA material based on gadolinium methacrylate has been developed and validated for large-scale mass production. This material will be implemented for the first time in the DarkSide-20k experiment, a liquid argon-based direct dark matter search. This poster will present the development process of Gd-PMMA, including a dedicated annealing procedure designed to release residual stress for cryogenic applications. Measures taken to control radiopurity during production will also be discussed.
Speaker: Lei Chen (IHEP, CAS) -
286
Helium Recycling System For SuperNEMO
The SuperNEMO Demonstrator is a double-beta-decay detector, currently taking physics data at LSM, France. It has a unique ability to measure the full topology of decay events, thanks to a tracking detector filled with a carefully-controlled gas mixture consisting of 95% ultra-pure helium, 4% ethanol, and 1% argon. To achieve SuperNEMO’s ambitious radiopurity target of 0.15 mBq/m$^{3}$, fresh gas is constantly flowed through a bespoke radon trap, and subsequently through the SuperNEMO detector.
In response to the recent helium shortage, the decision was made to recycle helium from SuperNEMO’s exhaust. This is particularly challenging as due to the design of the radon trap, all traces of ethanol must be removed from the SuperNEMO exhaust before it can be recirculated. This poster presents our innovative helium-recycling system, which uses a novel combination of cryogenic and adsorption techniques to reduce ethanol levels to below 1ppm. It explains how, through a bespoke control and monitoring system, it runs semiautomatically, maintaining our controlled gas composition, and dramatically reducing SuperNEMO’s helium consumption.
Speaker: Penghui Li (university of edinburgh) -
287
High energy multi-messenger signals from symbiotic novae
The detection of near-TeV gamma rays from the nova RS Ophiuchi (RS Oph) has confirmed that symbiotic novae (binary system of white dwarf and red giant stars) can act as TeV scale particle accelerators. However, the origin of these gamma rays, whether hadronic or leptonic—remains uncertain due to the non-detection a corresponding high energy neutrino signal. In the hadronic scenario, gamma rays and neutrinos are produced when high-energy protons accelerated in the nova shock interact with the ambient material. In this study, we analyse the detection possibility of the hadronic origin using current high-energy gamma-ray observatories (LHAASO, Fermi-LAT) and neutrino telescopes (IceCube, KM3NeT). We also examine an alternative mechanism in which protons from the nova wind are accelerated to high energies via magnetic reconnection occurring near the white dwarf's surface. In this scenario, high-energy gamma rays are expected to be fully absorbed by the dense environment, while neutrinos can escape unimpeded. We assess the detectability of these neutrinos and demonstrate that their spectral features differ significantly from those produced by shock-accelerated protons, making them distinguishable in detectors like IceCube and KM3NeT.
Speaker: Prantik Sarmah (Institute of High Energy Physics Beijing) -
288
High Speed 5GSps Pulse Shape Digitization Prototype Based on RFSoC
High-speed and high-precision pulse waveform digitization has extremely high application value in many fields such as nuclear physics experiments and medical imaging. The requirement for capturing picosecond-level pulses in the China Jinping Neutrino Experiment also poses extremely high demands on the pulse sampling rate. However, traditional solutions are mostly based on board-level circuits, adopting an architecture of analog pre-conditioning + high-speed ADC + FPGA (DSP) processor, which leads to high system complexity, low integration, high power consumption, and high design difficulty, and performs poorly in terms of system noise and high-speed transmission. To address these issues, this paper developed a high-speed pulse waveform digitization prototype based on RFSoC, achieving 5 GSps (Giga Sample per second) high-speed pulse waveform digitization. RFSoC integrates field programmable logic controller (PL), multi-core processor subsystem (PS), and eight-channel 5GSps/14-Bit analog-to-digital and 9.85GSps/14-Bit digital-to-analog converters (RFDC) in a single chip. Experimental results show that the high-speed pulse waveform digitization prototype based on RFSoC fully retains the pulse time-domain characteristics and can meet the strict requirements of dynamic range and time accuracy with 9.10-Bit ENOB at 347MHz input, 9.14-Bit at 10MHz input and 4GSps (compare to 8.56-Bit ENOB at 347MHz with ADC12DJ5200RF from TI). Compared with discrete solutions (4-Chip of ADC12DJ5200RF for 8-Channel 5GSps/12-Bit ADC with XCVU3P FPGA), this prototype reduces power density by 40%, reduces occupied area by 60%, and achieves sub-picosecond-level multi-channel synchronization accuracy, demonstrating extremely high application value in the field of high-speed pulse waveform digitization.
Speaker: Zhenxue Bian -
289
Integrate Sensor for Spherical Proportional Counter
The Spherical Proportional Counter (SPC), has a broad range of applications such as neutron detection; ßß0v (neutrino physics ) and Dark Matter search. The low background detectors like SEDINE (ø=60cm; SPC_60) and SNOGLOBE (ø=140cm; SPC_140), both fabricated at LSM and respectively installed at LSM and SNOLab (Canada, Sudbury), are taking data as light DM detector within NEWS-G collaboration. The next generation of SPC for DM search, will be a 300cm sphere, fully electroformed cupper in Boulby underground laboratory (UK). The goal of this study is to develop a new concept of a sensor with integrated electronic parts to reduce the parasite capacitor and electronic noise (for the SPC DM detection). According to our estimation, the noise should be reduced by 1 or 2 orders of magnitude in our ROI, which is Light WIMP search at low threshold. In this work, the electric field homogeneity simulation and some experimental result of the first prototype will be presented.
Speaker: Dr Ali DASTGHEIBI FARD (France CNRS/LPSC-LSM) -
290
Investigation of neutron background and the effect on dark matter search with a spherical proportional counter
The New Experiments With Spheres – Gas (NEWS-G) collaboration has designed the Spherical Proportional Counter (SPC) dedicated to searching low-mass weakly interacting massive particles (WIMPs), one of the most promising dark matter (DM) candidates. SPCs are gaseous detectors relying on ionization of light noble gases. In probing dark matter, neutrons become one of the significant background sources limiting detector sensitivity. The understanding of those sources is crucial for optimizing the background rejection strategies, to finally distinguish the rare events signal. In this work, we will focus on SEDINE, a low background DM SPC installed at Underground Laboratory of Modane (LSM, Laboratoire Souterrain de Modane) (4800 m.w.e). The detector principle, detector environment, the simulation results on environmental gamma background and a preliminary results of neutron background will be presented. All the efforts pave a way towards detector shielding improvement to enhance DM detection sensitivity.
Speaker: Mr Motlatsi Vincent Mahanyapane (Physics Department, Stellenbosch University, South Africa) -
291
JUNO as 2 MeV Water Cherenkov Detector
The Jiangmen Underground Neutrino Observatory (JUNO) is a large spherical liquid scintillator detector primarily designed to determine the neutrino mass ordering. Its central detector is a 35-meter-diameter acrylic sphere filled with 20 kilotons of organic liquid scintillator. The detector features over 17,000 20-inch PMTs and over 25,000 3-inch PMTs, with a total coverage area of 78%. Thanks to the high PMT coverage, the JUNO detector has the potential to achieve a high light yield and an extremely low energy threshold.
JUNO is expected to complete the filling of liquid scintillator and begin formal operation in 2025. Prior to filling the liquid scintillator, JUNO was first filled with pure water, during which a series of calibration experiments and data collection were conducted. This study analyzed the water-phase calibration data from Am-Be and Am-C radioactive sources. Neutron capture events have been observed. These results demonstrated that JUNO as water Cherenkov detector can achieve an energy threshold as low as 2.2 MeV.Speaker: Dian Li (中国科学院高能物理研究所) -
292
Kr85 Background Estimation for Solar pp Neutrino Measurement in XENONnT
XENONnT is a direct dark matter search experiment using 8.6 tonnes of Xe. Our observable energy threshold is few keV level, which enables us to search for physics in the low-energy electronic recoils, such as the search for events induced by solar pp neutrinos.
Kr85 is one of the background sources in such low-energy region. To achieve a high significance observation of rare physics events, a precise estimation of Kr85 abundance is required. This poster presents the method and results of the Kr85 background evaluation, and its impact on the sensitivity to solar pp neutrino measurement.Speaker: Yoshino Kaminaga (ICRR, The University of Tokyo) -
293
Low Noise Readout ASICs for Astroparticle Physics Research
Introduction for some Low Noise Readout ASICs for Astroparticle Physics Research developed by institute of high energh physics,CAS. They can be used with SDD,Si-PIN,Ge,CZT,GEM and SiPM detector. And some of them can be used for polarimetry of X-ray or Compton imaging.
Speaker: Ke WANG (Institute of High Energy Physics, CAS) -
294
Low-Threshold Analysis for Low-Mass WIMP Search with COSINE-100
The COSINE-100 experiment is a direct dark matter search using 106 kg of NaI(Tl) crystal detectors, each with a light yield of approximately 15 photoelectrons per keV. The experiment was operated at the Yangyang Underground Laboratory in Korea, collecting 6.5 years of data. A nominal analysis has achieved a clean energy threshold of 8 photoelectrons by rejecting PMT-induced noise events. To further enhance sensitivity to low-mass WIMPs, we aim to lower the effective analysis threshold to the hardware trigger level of 2 photoelectrons (approximately 0.13 keV) using annual modulation analysis. While PMT-induced noise remains at this threshold, it can be statistically separated from potential WIMP signals, which would exhibit seasonal modulation. In this presentation, we will present the current status of the low-threshold analysis, event selection techniques, and future prospects for probing low-mass WIMP-nucleon scattering using the full COSINE-100 dataset.
Speaker: Wonkyung Kim (University of Science & Technology (UST), IBS School) -
295
LZ & XLZD Low-E ER Sensitivity Projections
LUX-ZEPLIN(LZ) and its next generation XENON-LZ-DARWIN(XLZD) are designed to search for dark matter using two-phase liquid xenon time projection chambers. LZ has been processing its WS2024 upper-limits for dark matter candidates, like axion-like particles(ALPs). Meanwhile, XLZD has been projecting sensitivity for several signal’s models, including weakly interacting massive particles(WIMPs), solar axion, neutrinos, and ALPs. In this poster, I will show LZ most up-to-date upper-limits and XLZD projected sensitivities for signal models of low-energy electron-recoil(ER) group.
Speaker: Huan Zhang -
296
Measurement of the branching ratio of 16N, 15C, and 12B isotopes through the nuclear muon capture reaction in the Super-Kamiokande detector
The Super-Kamiokande detector has measured solar neutrinos for more than 25 years.The sensitivity to solar neutrino measurement is limited by the uncertainties of energy scale and the background modeling. One of the major background events is the spallation products created by the cosmic ray muons in the detector water tank. Some of the negative muons stop in the tank and are captured by the oxygen nuclei. Decays of unstable isotopes with relatively long half-life through the nuclear muon capture, such as $^{16}$N, $^{15}$C, and $^{12}$B, are detected as background events of solar neutrino observations.
In this study, we developed the method to form a pair of parent-stopping muon and decay candidate events and evaluated the production rates of such unstable isotopes. We then measured their branching ratio considering their production rates and the estimated number of nuclear muon capture.
The result of $^{16}$N is the world-leading precision measurement at present and the results of $^{15}$C and $^{12}$B are the first branching ratio measurements of those isotopes.
These measurement results are useful for improving simulations for muon capture processes.Speaker: Yuto Maekawa (Keio University) -
297
MeV-scale event-by-event direction reconstruction with Jinping 1-ton slow liquid scintillator prototype
The direction of individual AmBe $\gamma$ has been reconstructed using Jinping 1-ton prototype in slow liquid scintillator phase, with consideration of neutron-induced nuclear recoil effects. Through custom waveform analysis of readout signals, we extracted photoelectron (PE) information per trigger event, including PE number and time. Cherenkov and scintillation light were divided according to the PE time, and a maximum likelihood method was applied to reconstruct the direction of individual $\gamma$. The analysis reveals strong correlation between reconstructed particle directions and the position vectors connecting event vertices to the AmBe position. This event-by-event reconstruction capability enables new approaches to neutrino source directionality measurements and improves background discrimination in MeV-scale neutrino experiments.
Speaker: Yutao Zhu (Tsinghua University) -
298
Modeling of Low Temperature and Low Noise Devices
With the continuous advancement of research on deep subsurface dark matter, low-background and low-noise detection devices have become the mainstream and hotspot of research. Low noise, high-density, arrayed sensing and amplification devices that can meet high sensitivity and energy resolution have become the key research objects of detection devices. InP devices have excellent low-temperature electrical properties and low noise performance due to physical characteristics such as conduction band discontinuity at the heterojunction InAlAs/InGaAs interface, high two-dimensional electron airtightness, high electron mobility in the channel, and small differences in thermal expansion coefficients of lattice matching systems. Our research group has conducted research on low-temperature modeling techniques for InP devices. Including low-temperature small signal equivalent circuit model, low-temperature noise matrix, and physical meaning of the model; Low temperature small signal equivalent circuit model parameter extraction technology, including intrinsic component parameter extraction, parasitic capacitance, inductance, and resistance parameter extraction. At the same time, using artificial neural network models to learn low-temperature passive device models has improved the modeling speed and scaling accuracy of the models. It can provide accurate low-temperature device parameters for the design of low-temperature front-end circuits, which is of great significance for shortening the design cycle, reducing design costs, and improving reliability.
Speaker: Prof. 仲茂 李 (中国科学院微电子研究所) -
299
Muon-induced backgrounds in the AMoRE-II underground detector
Muon-induced backgrounds present a substantial challenge for rare-event searches like neutrinoless double beta decay. To substantially reduce these backgrounds, the AMoRE-II experiment is located approximately 1,000 meters underground at the Yemilab facility in Korea. AMoRE-II employs low-temperature lithium molybdate crystal detectors along with complementary detection systems, including a plastic scintillator muon detector (PSMD) and a water Cherenkov detector (WCMD), to achieve unprecedented sensitivity levels.
This preliminary investigation addresses muon bundles—simultaneous arrivals of multiple muons originating from high-energy cosmic ray interactions in Earth's atmosphere—and evaluates their contributions relative to the overall muon-induced background observed in AMoRE-II. Employing comprehensive Monte Carlo simulations utilizing Geant4 and MUTE software frameworks, along with initial analyses of experimental data obtained predominantly from PSMD and WCMD, this study aims to quantify the occurrence rates, multiplicities, and energy deposition characteristics of muon bundles at the detector site.
In this presentation, we outline our methodological approach, present initial simulation outcomes, and provide preliminary quantitative assessments of muon bundle-induced backgrounds. While muon bundles are expected to comprise a minor fraction of the total muon-induced background, their precise characterization is critical for developing an accurate background model and effective mitigation strategies. These preliminary results lay the groundwork for future in-depth examinations of muon-induced backgrounds in the AMoRE-II experiment.
Speaker: Jeewon Seo -
300
Neganov-Trofimov-Luke light detectors in 0νbb experiments
In bolometric experiments searching for neutrinoless double-beta decay (0νββ), light detectors are used to identify and discriminate between particle interactions by simultaneously detecting heat and scintillation light. This dual-readout approach is crucial for suppressing background signals, particularly for distinguishing α particles from β/γ events, thereby enhancing sensitivity to rare decay signatures.
Luminescent bolometers—consisting of a primary energy absorber containing the double-beta decay isotope and an auxiliary cryogenic light detector—represent a leading technology in this field. They are central to experiments such as BINGO, CROSS, and CUPID.
To improve the performance of cryogenic light detectors in these experiments, the Neganov-Trofimov-Luke (NTL) effect is employed. By applying an electric field across a semiconductor absorber, the NTL effect amplifies the thermal signal through the drift of photo-generated charges. This significantly enhances the signal-to-noise ratio without introducing additional thermal noise, enabling the detection of extremely faint luminescent signals. This amplification is particularly valuable for improving background rejection, including efficient pile-up discrimination.
Ongoing R&D efforts focus on optimizing NTL light detectors (NTL LDs) to meet the performance requirements of CROSS, BINGO, and CUPID. These detectors are tested at cryogenic temperatures with various electrode designs to study their signal gain and their ability to sustain high voltage bias.This poster presents the development of both Ge and Si light detectors, from bare wafers to fully functional devices incorporating NTL amplification. It highlights the fabrication processes, performance characterization, and key experimental results.
Speaker: Hawraa Khalife (IRFU (CEA Paris-Saclay)) -
301
Neutrino Detector Response Modeling with Several Advanced Machine Learning and Statisical Methods
Liquid-scintillator neutrino detectors made significant contributions in the discoveries of neutrino physics. Reconstruction of neutrino energy and position demands point-source response function (probe) of the photoelectrons reception on photomultiplier tubes. We model the probe with inhomogeneous Poisson process for calibration from Monte Carlo simulated data. To achieve higher precision and ensure continuity and differentiability, we investigate several advanced machine learning and statisical methods and find the Generalized Additive Model demonstrates the best performance among the other studied approaches including neural networks and boosted decision tree.
Speaker: 传晖 郝 (清华大学) -
302
Neutrino-Oxygen interaction measurement at the Supernova neutrino energy regime with Spallation Neutron Source in Oak Ridge National Laboratory
Neutrino observations from nearby supernova (SN) bursts in underground detectors, such as Super-Kamiokande and future Hyper-Kamiokande, play a key role in understanding the SN explosion mechanism.
However, the neutrino-oxygen interaction in a few tens of MeV, which is the target energy region of SN neutrinos, is not well measured, and the neutrino information cannot be fully obtained from the precious SN burst. Therefore, a detailed understanding of this reaction is essential to maximizing supernova neutrino observations.
A new neutrino cross-section measurement is proposed using the Spallation Neutrino Source (SNS) in Oak Ridge National Laboratory (ORNL).
This poster reports the current results of a prototype test in Kamioka, Japan, and prospects for the ORNL measurement plan.Speaker: Masayuki Harada (ICRR, The University of Tokyo) -
303
Neutron Capture Information in Improving IBD Angular Resolution
One of the most important neutrino interactions is the Inverse Beta Decay (IBD). However, the IBD events typically carry no directional information in water Cherenkov detectors as the positrons direction is mostly isotropic at low energies, such as those in supernova studies. As Gadolinium is being added to Super Kamiokande, the improved neutron capture efficiency not only allows better background rejection, but the neutron capture information could potentially provide additional information that allows better event reconstruction. Due to neutron diffusion in water, event by event reconstruction is difficult. However, if the final neutron capture position is correlated with the initial neutrino momentum, it may be possible that neutrino directionality could be reconstructed statistically, with or without using the positron information. In this work, we use Geant4 to simulate neutron propagation in water. We show that in a wide range of neutrino energy from about 10 MeV to several hundred MeV, neutron capture information could statistically enhance the neutrino directionality, compared to positron-only inference, even with neutron diffusion in water. However, practical application of this technique depends crucially on detection effects, particularly the vertex reconstruction resolutions. Our work therefore motivates developments of better reconstruction algorithms and techniques, as well as detector upgrades.
Speaker: Qishan LIU -
304
NEWAGE: Status of underground direction-sensitive dark matter search with low-background gaseous TPC
The sensitivity of the direct dark matter search is being improved by various energy-sensitive experiments such as XENONnT, LZ, Panda-X and so on. In parallel, direction-sensitive dark matter searches are designed and taken place to reveal properties of the dark matter particle after its discovery or to explore beyond the neutrino fog. NEWAGE is one of the direction-sensitive WIMP search experiments using three-dimensional tracking gaseous TPC, placed in the Kamioka underground observatory. Recently we developed low RI emission micro pattern gas detector. The new detector was installed in the Kamioka underground observatory and the final commissioning was started. We will present the status of the underground dark matter search and its prospects.
Speaker: Ryota Namai (Kobe University) -
305
Observation of solar radio bursts in the Radio Neutrino Observatory Greenland (RNO-G)
The Radio Neutrino Observatory Greenland (RNO-G) is an in-ice neutrino detector currently under construction. It is designed to detect ultra-high-energy neutrinos with energies exceeding ∼10 PeV , and currently 8 of the foreseen 35 stations have been deployed and are taking data. This contribution discusses observations of solar radio bursts by RNO-G stations, which include both deep antennas (up to 100 m in the ice) and near-surface antennas, operating in the 80–700 MHz frequency range.
While solar radio bursts represent a background for neutrino detection, they also can serve as a calibration source due to the known position of the Sun. Additionally, in RNO-G the high sampling rate of the recorded waveforms enables the study of radio bursts with nanosecond-scale temporal resolution.
We present examples of impulsive signals recorded during solar radio bursts with RNO-G in the summer periods of 2022 and 2023. The reconstruction of signal directions and results of antenna position calibration using solar flares are also discussed.
Speaker: Maria Mikhailova -
306
On the detection strategy of inclined air showers induced by ultra-high-energy particles
The complex system composed of millions of electromagnetic particles in cosmic rays provides a free laboratory for studying fundamental particles. Research on this system has greatly promoted the development of physics over the past century and has also provided powerful research tools for high-energy physics and multi-messenger astronomy. Using simulated data, we have identified a new fundamental effect generated by electromagnetic particles—the geosynchrotron radiation in inclined air showers, resulting from strong magnetic fields. This discovery opens new research pathways for next-generation ultra-high-energy particle detection experiments and introduces new challenges for the reconstruction of cosmic rays incident at large zenith angles. Based on this work, we have optimized the correction factor for energy reconstruction in radio detection, achieving an initial primary energy reconstruction accuracy better than 10%. Meanwhile, by accounting for both atmospheric and magnetic effects, we have developed a new model that can accurately predict muon deflections in cosmic rays and facilitate mass resolution of cosmic rays.
Speaker: Dr Chao Zhang (Nanjing University) -
307
Performance Evaluation of a New Sensor for the T2K Muon Monitor in Neutrino Beam Direction Measurements
T2K is a long-baseline experiment using J-PARC neutrino beam to study neutrino oscillations with the near detectors and the Super-Kamiokande detector as the far detector. The T2K experiment uses a muon monitor (MUMON) to indirectly monitor the neutrino direction and intensity. Upgrade of the J-PARC beam is currently ongoing towards a measurement of CP violation in the neutrino sector.
While MUMON has successfully been used for measurements at the current beam intensity, we expect certain issues with MUMON sensors in future operation at higher intensities, such as radiation damage. Sensors that are more radiation tolerant are desired for future operation of MUMON. Electron multiplier tubes (EMTs) are one candidate. It has been demonstrated by beam tests that EMTs have higher radiation tolerance than the currently used sensors. These results suggest that EMTs fulfill the requirements for MUMON at future beam intensity [1].
Based on these results, we have proceeded with the installation of EMTs in the neutrino beamline at J-PARC and test of the performance as a muon beam monitor. The results of muon beam measurements using these EMTs during T2K neutrino beam operation will be presented.[1] T. Honjo et al., “Performance Evaluation of Electron Multiplier Tubes as a High-Intensity Muon Beam Monitor of Accelerator Neutrino Experiments,'' PTEP 2024, no.12, 123H01 (2024)
Speaker: Yukine Sato (Tokyo University of Science) -
308
Performance Study of Orthogonal-Strip Planar HPGe Detectors for 76Ge Neutrinoless Double-Beta Decay Searching
Searching for neutrinoless double-beta (0νββ) decay is considered a promising approach for proving the Majorana nature of neutrinos. Background suppression is particularly important in 0νββ decay searches, which are considered rare-event searches. For traditional single-electrode high-purity germanium (HPGe) detectors, pulse shape analysis methods such as A/E are effective in distinguishing between single-site and multi-site events. However, they are inadequate for separating single- and double-electron events because of insufficient position resolution. Orthogonal-strip planar HPGe detectors, which offer excellent energy resolution, low background, high detection efficiency, and, most importantly, three-dimensional position sensitivity, are ideal for 0νββ searches. In this work, we developed a waveform simulation platform for orthogonal-strip planar HPGe detectors to systematically study their response to single- and multi-site events, as well as to single- and double-electron events. Furthermore, key detector parameters, such as electrode configuration and crystal thickness, were optimized to improve performance in 76Ge 0νββ detection. Our results demonstrate the feasibility and advantages of applying orthogonal-strip planar HPGe detectors for 0νββ detection, providing valuable guidance for future detector design.
Speaker: Qiuli Zhang (Tsinghua University) -
309
Performance Validation of the VSTT: An Upgraded CUPID Prototype Tower with Neganov-Luke Enhanced Light Detectors
The CUPID collaboration is advancing toward a next-generation cryogenic bolometric experiment for neutrinoless double beta decay searches, based on $^{100}$Mo-enriched scintillating crystals.
Building on the experience of the first prototype (GDPT), a new upgraded tower has been developed. The Vertical Slice Tower Test (VSTT) features an upgraded mechanical structure designed to improve the uniformity of thermalization across the array and to suppress correlated noise among the light detectors (LDs).
The VSTT employs LDs equipped with Neganov-Luke amplification to significantly boost light signal sensitivity. This advancement is crucial for enhancing the rejection of $2\nu\beta\beta$ pileup events—a major challenge for CUPID due to the high decay rate of $^{100}$Mo and the intrinsically slow thermal response of the calorimetric detectors.
The tower will be operated in the CUPID wet cryostat at LNGS Hall A and instrumented with optical fibers, dedicated thermometry, and vibrational sensors. These systems will enable a full characterization of thermal behavior, optical performance, and vibrational noise.
The VSTT results will be pivotal in validating the technological solutions for the final CUPID detector design.Speaker: Irene Nutini (Istituto Nazionale di Fisica Nucleare - Milano Bicocca) -
310
Plastic scintillator cosmic ray anti-coincidence system in RECODE experiment
Coherent Elastic Neutrino-Nucleus Scattering(CEvNS) is an important scientific frontier in the field of particle physics. We conducted CEvNS experiments around the RECORDE high-purity germanium reactor and developed a plastic scintillation counter anti-coincidence detector to suppress the background of cosmic rays. For large volume plastic scintillation detectors, research has optimized scintillation light collection technology based on moving wave fibers, achieving detection efficiency of over 99% for cosmic ray muons and anti-coincidence efficiency of over 98%.
Speakers: Mr Enyi Xie (Beijing Normal University), Ms Xiaoxue Yan (Beijing Normal University), Yantao Wang (Beijing Normal University) -
311
Preliminary Design of Multi Channels High Precision Measurement Electronics System for CJPL
Multi Channels 24-Bit/2 MSps high precision electronics system is designed for demand of CJPL to measure the analog signals such as high voltage, particle accelerator magnet current. Based on the dual FMC carrier board of WRX602, we present the preliminary design of 4-Channel 24-Bit/2 MSps FMC. The state-of-the-art 24-Bit SAR ADC of AD4630-24 from ADI is used and a cascade front signal conditioner with programmable instrumentation amplifier and differential ADC driver is deployed for best noise and distortion with relaxed drive requirement for signal source. On-board LT6655 voltage reference to AD4630-24 and drive the REFIN pin through an R-C filter to reduce low frequency noise and external reference with the best voltage reference nowadays ADR1001 can be used for comparison. The preliminary result of 100-dB SNR can be reached and more details will be reported in this paper.
Speaker: Bo Liang (Tsinghua University) -
312
Production of ultra–low-background NaI(Tl) crystals for the SABRE experiment
The SABRE experiment aims to perform a model-independent search for dark matter using arrays of ultra–low-background NaI(Tl) crystals.
The expected background rate in the ROI [1–6] keV is on the order of 0.5 dru. To achieve this level of radiopurity, SABRE North will make use of zone refining purification process of the NaI powder.
The SABRE North collaboration has recently validated, through a series of tests, the technology for producing 5 kg NaI(Tl) crystals following zone refining purification and is now starting crystal production for the experiment. The first crystal grown using this technology is expected to be produced and delivered to LNGS in July 2025 for characterization.
Poster will present the current status of this development and initial results.Speaker: Krzysztof Szczepaniec (I.N.F.N. Laboratori Nazionali del Gran Sasso) -
313
Progress on the Readout Electronics and Data Acquisition System for the NνDEx-100 Experiment
The NνDEx-100 experiment is designed to search for neutrinoless double-beta (0νββ) decay using a high-pressure gaseous time projection chamber with SeF6 as the target medium. The detector features a front-end readout system comprising 8,192 sensors organized into 32 modular units within a single end-cap. These sensors perform ion collection and signal amplification, generating analog pulses that are continuously digitized by multi-channel ADCs. Each module incorporates a SerDes chip for data aggregation through oversampled SPI interfaces. The complete readout system employs 32 bidirectional 2.5 Gbps optical links connecting the front-end electronics to the DAQ system. Implemented via dual PCIe cards in a server configuration, the DAQ provides real-time control and continuous readout for all front-end modules. System validation has confirmed the full signal chain from sensor to event processing servers, including successful demonstration of direct ion tracking without avalanche amplification. This presentation will detail recent progress in sensor design and characterization, highlight outstanding technical challenges, and provide a comprehensive status report on the front-end electronics and DAQ system development.
Speakers: Lei Lang (Central China Normal University), Kai Chen (Central China Normal University), Chaosong Gao (Central China Normal University) -
314
Purity control and measurement in liquid xenon detectors
The RELICS experiment employs a dual-phase xenon time projection chamber (TPC) to investigate Coherent Elastic Neutrino-Nucleus Scattering (CEνNS) signals from reactor neutrinos. To improve the sensitivity of the detector, the liquid xenon in TPC needs to be ultra-pure. Electronegative impurities, induced by outgassing, can absorb the electrons created by article interactions inside the detector, diminishing the potential CEνNS signals. In order to control the xenon purity, we studied the outgassing character of main materials in TPC and techniques to reduce the oxygen outgassing rate through systematical vacuum tests. Additionally, we developed a purification model to predict and monitor xenon purity evolution. Our findings enable effective xenon purity enhancement in the RELICS prototype, ultimately improving the LXe detector efficiency and sensitivity.
Speaker: 景凡 谷 (清华大学) -
315
Radon Reduction Strategies and Detection Techniques for Ultra-Clear Liquid Nitrogen in the CDEX Experiment
Liquid nitrogen is regarded as a radioactivity-free material with minimal concerns related to cosmic-rays; however, radon emissions from shielding and potential leaks can still pose challenges in the search for dark matter and neutrinoless double beta decay in the CDEX experiments. Achieving radon activity levels below sub-μBq/kg is a key milestone for current rare event experiments. We have developed two methods for detecting low concentrations of radon: one using a 300-ml liquid scintillator with a background level of 30 micro-Bq, and the other utilizing a 100 L electrostatic collection chamber with a radon concentration of 0.08 mBq/m³ in gas. With the application of cryogenic activated carbon enrichment, sensitivity can be further enhanced to the sub-μBq/kg range. We will discuss radon reduction strategies and insights into radon transport.
Speaker: Qianyun Li (Sichuan University) -
316
Recent R&D Progress Towards a Bolometric 0νββ Experiment at China Jinping Underground Laboratory
The search for neutrinoless double-beta decay (0νββ) could shed light on fundamental questions including the Majorana nature of neutrinos, potential lepton number violation, and the matter-antimatter asymmetry in the universe. Scintillating bolometers, with their excellent energy resolution and background discrimination capabilities, represent a promising technology for next-generation 0νββ experiments. We present recent collaborative efforts in China to develop scintillating bolometers for 0νββ searches, including ground-lab R&D tests and simulation studies. Current work focuses on establishing the basic performance characteristics of detector modules through ground-lab R&D and simulation studies. These development efforts will inform the design of a future experiment at the China Jinping Underground Laboratory (CJPL), with the ultimate goal of achieving high-sensitivity 0νββ searches.
Speakers: Keyu Shang (Fudan University), 芳 谢 (复旦大学) -
317
Reducing Systematic Uncertainties in Neutrino Detection with the Water Cherenkov Test Experiment (WCTE)
The Water Cherenkov Test Experiment (WCTE) is a 30 ton water Cherenkov detector currently installed in the T9 beamline at CERN. It has been built as a prototype of the Intermediate Water Cherenkov Detector (IWCD) for the Hyper-Kamiokande long-baseline neutrino oscillation experiment. For Hyper-Kamiokande to achieve its physics goals, systematic uncertainties in the detection and reconstruction of neutrino events must be reduced below current levels. WCTE is measuring the interaction of charged particles and photons in a water Cherenkov detector to reduce systematic uncertainties in neutrino detection. Charged electrons, muons, pions and protons between 200 MeV and 1.5 GeV are characterized by an array of beam monitors before entering the water Cherenkov detector. WCTE measures the water Cherenkov detector response to these particles and studies their reconstruction. WCTE can also measure the scattering cross sections of charged leptons and pions in water which can be used to constrain neutrino interaction models and improve neutrino event reconstruction. Additionally, measurements are made with a tagged-gamma beam to study the separation of gamma and electron events in water Cherenkov detectors and gadolinium doped water to study the production and interaction of neutrons in neutrino detectors. This talk will discuss the physics goals of the WCTE experiment and show some preliminary results from data taken in spring 2025.
Speaker: Laurence Cook (TRIUMF) -
318
Research of large balloon production for KamLAND2
KamLAND is a neutrino detector containing a 1-kiloton liquid scintillator, located 1000 meters underground at the Kamioka Mine. The experiment completed 22 years of data acquisition in August 2024. The KamLAND2 experiment, scheduled to start in fiscal year 2027, aims to further improve light collection efficiency by increasing the luminous flux of the liquid scintillator, introducing high quantum efficiency photomultiplier tubes (PMTs), and utilizing focusing mirrors for the PMTs. Additionally, the 13-meter-diameter balloon film containing the liquid scintillator will be remanufactured for KamLAND2. The same material and design as the proven KamLAND balloon will be used, but new measures will be implemented to reduce background contamination from the detector. These measures include the introduction of a cover film to prevent contamination during manufacturing at installation. EVOH, the material used for the surface of the balloon film, has high gas barrier properties to prevent the infiltration of (_^222)Rn from the outside. However, EVOH also has high hygroscopic properties, raising concerns that its characteristics may change in the high-humidity environment expected to prevent static electricity. Therefore, this study will investigate the effects of moisture on EVOH and the balloon film, ultimately evaluating the humidity requirements for the balloon with the cover film during production. A comprehensive overview of the balloon production process will also be presented.
Speaker: Natsu Obata (Research Center for Neutrino Science, Tohoku University, Japan) -
319
Results from the DsTau(NA65) experiment at the CERN-SPS
The DsTau(NA65) experiment at CERN aimed to measure an inclusive differential cross-section of Ds production with decay to tau lepton and tau neutrino in proton-nucleus interactions. The DsTau detector is based on the nuclear emulsion technique, which provides excellent spatial resolution for detecting short-lived particles such as charmed hadrons. We present the first results from the analysis of data collected during the pilot run in 2018 and discuss the accuracy of reconstructing proton interaction vertices in a high track density environment. The gathered data has been compared with several Monte Carlo event generators, with a focus on the multiplicity and angular distribution of charged particles. The multiplicity distribution from p–W interactions has been tested for KNO scaling and was found to be nearly consistent. Additionally, we performed the first measurement of the interaction length of protons in tungsten. We also present the current status of our search for Ds decay and provide preliminary estimates of the differential production cross-section of Ds.
Speaker: Ali Murat Guler (Middle East Technical University) -
320
SDDs for the measurement of forbidden β spectra of interest to astroparticle physics
The ASPECT-BET project, or An sdd-SPECTrometer for BETa decay studies, aims to develop a novel technique for the precise measurement of forbidden β spectra in the 10 keV–1 MeV range. Accurately measuring a set of β spectra from different isotopes using the same setup can help in ruling out those nuclear models unable to predict the spectral shapes. Experiments in the field of 0𝜈ββ, WIMP, and Reactor neutrino oscillation searches would greatly benefit from such measurements, usable to help find a reliable nuclear model.
The ASPECT-BET technique employs a Silicon Drift Detector (SDD) as the main spectrometer with the option of a veto system to reject events exhibiting only partial energy deposition in the SDD. The SDD is optimized for higher efficiency, having an active area of 64 mm$^2$ and a thickness of 1 mm, specifically designed to contain electrons with energy up to 1 MeV. These detectors can be operated at room temperature, exhibiting an excellent energy resolution (~200 eV at 5.9 keV), thus allowing measurements of fast-decaying isotopes, non accessible with other state-of-the-art techniques based on cryogenic detectors.
A precise understanding of the spectrometer’s response to electrons is crucial for accurately reconstructing the theoretical shape of the beta spectrum. To compute this response, GEANT4 simulations optimized for low-energy electron interactions are used. These simulations have been extensively validated with measurements taken with both artificial and radioactive electron sources. In this poster, we present the performance of these simulations in reconstructing the electron spectra measured with the ASPECT-BET SDDs. In particular, the allowed beta spectrum of a 14C source was measured and analyzed, proving that this system is suitable for the application in ASPECT-BET. The non-unique 2nd forbidden 99Tc β spectrum was also measured, and the status of its interpretation based on different nuclear theories will be shown as well.Speaker: Andrea Nava (University of Milano-Bicocca) -
321
Sensitivity of search for double beta decay of 130Te to excited daughter state in CUORE
Double beta decay to an excited state of the daughter nucleus may be considered in addition to the more probable decay to ground state. Though it suffers from a reduced phase space, the decay to an excited state has a unique experimental signature, distinguished by coincident gamma rays from the de-excitation of the daughter nucleus. So far, the two-neutrino excited state decay has only been observed in $^{150}\textrm{Nd}$ and $^{100}\textrm{Mo}$. The Cryogenic Underground Observatory for Rare Events (CUORE) is an array of 988 crystals of $\textrm{TeO}_2$ operated at millikelvin temperatures, with each crystal serving as both a source and a calorimetric detector. The segmented nature of the CUORE detector provides a distinct setting to search for excited state decays, with coincident energy depositions in more than one crystal. This coincidence signature provides a complementary test of the nuclear physics of double beta decay with much reduced backgrounds compared to decays to a final ground state. Here, I will report on sensitivity studies on a search for double beta decay of $^{130}\textrm{Te}$ to the lowest $0^+$ excited final state of $^{130}\textrm{Xe}$ with 2 tonne-years of data.
Speaker: Ridge Liu (Yale University) -
322
Simulation and Design of a Water Cherenkov Veto for the PandaX-xT Experiment
PandaX-xT is a next-generation, multi-purpose liquid xenon detector at China Jinping Underground Laboratory. It is designed with a 43-ton active target mass and ultra-low background to achieve a high sensitivity for dark matter detection and neutrinoless double-beta decay search. As a passive shielding, 4 kton of water will be filled in the water pit where the liquid xenon detector is situated. By instrumenting 3-inch PMT arrays in water, one can transform it into a Cherenkov veto detector which can tag cosmic muons as well as atmospheric neutrinos. A simulation framework has been developed to optimize the design and achieve optimal detection performance. This poster presents the simulation, reconstruction, and a preliminary design for this veto detector.
Speaker: Yuxin Tian (School of Physics and Astronomy, Shanghai Jiao Tong University) -
323
Simulation study for the N$\nu$DEx Experiment: A Search for Neutrinoless Double Beta Decay of Se-82 Using a High-Pressure Gas TPC
N$\nu$DEx experiment aims to search for the 0νββ of $\mathrm{^{82}Se}$ using high pressure $\mathrm{^{82}SeF_6}$ gas TPC. Accurate track simulation and reconstruction is essential for the study of background rejection and signal identification. In this work, we present a simulation framework and preliminary study of the signal and background discrimination for the N$\nu$DEx experiment, which includes:
- Calculation of reduced mobilities of $\mathrm{SeF_{5}^{-}}$ and $\mathrm{SeF_{6}^{-}}$ in $\mathrm{SeF_{6}}$. The reduced mobility for $\mathrm{SeF_{5}^{-}}$ and $\mathrm{SeF_{6}^{-}}$ in $\mathrm{SeF_{6}}$ are calculated using Avogardo, Gaussian16 and IMoS softwares based on the Mason-Schamp equation.
- TPC geometry with 10k sensors readout array. Both the weighting and electric fields of the TPC are constructed in COMSOL Multiphysics.
- Simulation of signal and background events in the gas using Geant4.
- Transportation of charge carriers in the gas. The Garfield++ is used for the charge transportation in the gas and to calculate the induced current in each of the 10k sensors.
- Sensor Response and 3-d track reconstruction. The induced current of each sensor is converted to the voltage signal using practical sensor parameters. While the x-y coordinates are determined by the sensor positions in the readout plane, the z coordinate is reconstructed utilizing the difference of velocities between $\mathrm{SeF_{5}^{-}}$ and $\mathrm{SeF_{6}^{-}}$.
- Background and signal event discrimination. Preliminary results show promising separation between signal and background based on the features of reconstructed 3D tracks. Further studies are ongoing, exploiting various methods.
Speaker: tianyu liang -
324
Status of the development of the water tank Instrumentation of LEGEND1000
The LEGEND-200 experiment is a neutrinoless double beta decay (0νββ) search experiment located in the Laboratori Nazionali del Gran Sasso in Italy. LEGEND uses a maximum of 200kg of 76Ge enriched germanium mono-crystals as both source and detector for double beta decays. These crystals are housed in a cryostat filled with liquid argon to provide an optimal operation environment as well as a first stage muon veto. A surrounding water tank is used as both as a shielding against backgrounds and as a second stage muon (Cerenkov) veto.
The next stage of LEGEND will be LEGEND-1000, which will increase the detector mass to one tonne. Additionally, the experiment will be housed in a completely new setup which provides the opportunity to optimize the design of the support installations and the experimental instrumentation to the needs provided by the results of LEGEND-200.
This contribution will provide an overview of the current status of the water tank instrumentation development for the next stage of the experiment. It will focus on the water Cerenkov veto, the neutron tagger and the general water tank instrumentation geometry.Speaker: Tobias Sterr (Eberhard Karls University Tübingen) -
325
Study of cryogenic light detector based on germanium for heat-light double readout bolometers
A well-perfoming light detector are an essential prerequisite for the light-heat dual readout scheme and are therefore critical components of cryogenic crystal bolometers. Given the current lack of domestic experience in developing cryogenic light detectors, this project is dedicated to the research of germanium-based light detectors for cryogenic bolometer, which includes
- Investigation and establishment of a basic technical approach for semiconductor germanium-based light detectors.
- Design for surface anti-reflection coatings using silicon nitride (SiN𝑥) as the coating material, and study of the optical performance of the detectors (with thin films)at room temperature.
- Design and assemby of the cryogenic light detectors, installation onto a dilution refrigerator platform, conducting tests at ultra-low (mK) temperatures to characterize their response.
Speaker: Mr Deyong Duan (University of Science and Technology of China) -
326
Study of delayed electron background in liquid and gaseous xenon detectors
Coherent elastic neutrino-nucleus scattering (CEνNS) signals have extremely low energy threshold, and so controlling the background in the low-energy region is crucial for the detection. RELICS is an experiment aiming to detect CEνNS signals from reactor neutrinos on the ground using a dual-phase liquid xenon time projection chamber detector. Delayed electron is one of the most significant backgrounds. In order to study its distribution pattern and generation mechanism, we analyse data form RELICS prototype. The result shows that Delayed Electrons are correlated with previous high energy events in time and position. Drift time of electrons, liquid xenon purity and extraction field will also affect Delayed Electrons emission. Based on the spatial and temporal correlation with high-energy events, a data selection method is designed, which can reduce the background event rate in the CEνNS energy region by 1 to 2 orders of magnitude.
Speaker: Yang Lei (Tsinghua University) -
327
Study of Ionization Channel Signals for Dual-Phase Argon TPC
The dual-phase argon time projection chamber (DArTPC) has shown exceptional sensitivity and background rejection capabilities, as demonstrated by the DarkSide-50 experiment. For future dark matter detection, particularly for low-mass dark matter (<10 GeV/c²), exploiting exclusive ionization signal detection (S2-only) to achieve a low detection threshold is an exciting avenue of research. In this poster, we will present the ongoing R&D efforts focused on studying the S2 signal in a dedicated TPC setup. The current status of the experiments, including preliminary results on X-Y reconstruction, event selection, and pulse shape analysis will be discussed.
Speaker: YiKe Shu (Institude of high energy physics, Chinese academy of science) -
328
Study of the influence of mirror birefringence effect on KAGRA
The Japanese gravitational wave detector KAGRA is a 2.5-generation detector built underground using cryogenic techniques. Cooling down test masses to cryogenic temperatures is a way to reduce the thermal noise of gravitational wave detectors. Crystalline materials are considered the most promising materials for fabricating cryogenic test masses and their coatings because of their excellent thermal and optical properties at low temperatures. However, birefringence owing to local impurities and inhomogeneities in the crystal can degrade the performance of the detector. In this poster, we introduce our study on the influence of birefringence effect on the performance of the KAGRA detector.
Speaker: Dr Haoyu Wang (Institute of Science Tokyo) -
329
Study on XY Position Reconstruction in DArTPC with Au Dots Calibration
In the field of direct detection of light dark matter (DM) with masses below 10 GeV/c², the DarkSide-50 experiment, based on a dual-phase argon time projection chamber (DAr-TPC), has demonstrated competitive performance. Building on DarkSide-50, the DarkSide-LowMass experiment will focus on achieving low-threshold measurements and is projected to extend the search for light DM down to the neutrino fog region, spanning masses from sub-GeV/c² to around 10 GeV/c². To accurately identify the corresponding low-energy responses, both high detector performance and precise calibration of the argon ionization yield for nuclear recoil (NR) events are essential. To meet the demands of such low-threshold experiments with argon detectors, we are preparing an experiment using a small DAr-TPC to investigate various factors affecting the detector’s performance at low thresholds. Additionally, we aim to calibrate the liquid argon ionization response for nuclear recoils in the sub-keVnr energy region with a pulsed neutron beam. This poster will introduce the current status of the setup construction, the method to calibrate XY reconstruction with Au dots, and the preliminary testing results of the system.
Speaker: Jilong Yin (Institute of High Energy Physics - CAS) -
330
The accelerated Reactor fitter and Oscillation analysis for JUNO
The Jiangmen Underground Neutrino Observatory (JUNO) is a multipurpose liquid scintillator detector located 700 meters underground in Jiangmen, Guangdong Province, China. It is designed to achieve an exceptional energy resolution of $3\%/\sqrt{E\left(\mathrm{MeV}\right)}$. The primary goals of JUNO are to determine the neutrino mass ordering and to achieve sub-percent precision measurements of key neutrino oscillation parameters $\Delta m_{31}^2$, $\Delta m_{21}^2$, $sin\theta_{12}^2$. JUNO detects reactor antineutrinos primarily via the inverse beta decay (IBD) process, and is also capable of studying atmospheric, solar, and geoneutrinos, as well as supernova neutrinos.
This poster presents two main aspects: the development of a fast PyTorch-based fitter optimized with advanced computing techniques, enabling large-scale Monte Carlo simulations and significantly accelerating the neutrino oscillation analysis process; and the application of statistical methods for oscillation parameter analysis in JUNO, particularly under low-statistics conditions.Speaker: Jingqin Xue (Institute of High Energy Physics, CAS) -
331
The XENONnT Neutron Veto
For direct dark matter search experiments, radiogenic neutrons from
the detector materials are one of the most significant background
sources, since they mimic nuclear recoil signals by weakly interacting
massive particles.
In the XENONnT experiment, the xenon dual-phase time projection
chamber (TPC) is enclosed by a gadolinium-doped water Cherenkov
detector, neutron veto (nVeto), to tag such neutrons by detecting
Cherenkov lights from Compton-scattered gamma rays released after the capture of
neutrons on gadolinium or hydrogen.
The XENONnT nVeto showed the neutron tagging efficiency of (53±3)% in
its pure water phase, and almost 80% in its 0.02% gadolinium-loaded
phase (preliminary).
In this poster, details of the detector configuration, the calibration
method to estimate the tagging efficiency, and the achieved results
are presented.Speaker: Masashi Yoshida (The University of Tokyo, ICRR) -
332
Theoretical Constraints and Their Implications for Neutrinoless Double-$\beta$ Decay Probes
Next-generation neutrinoless double beta decay (0$\nu\beta\beta$) experiments are poised to achieve sensitivities that fully explore the inverted mass hierarchy (IH) parameter space and begin probing the normal mass hierarchy (NH) region, marking a significant advancement in the search for Majorana neutrinos, revealing the absolute neutrino mass scale, and lepton number violation [1, 2]. Achieving this long-sought discovery is plausible provided that theoretical ambiguities, especially in the nuclear matrix elements, the axial-vector coupling, and phase space contributions, are negligible or if the underlying physics favors the most optimistic scenario. Conversely, if the axial-vector coupling constant is subject to maximal quenching, nuclear matrix elements assume the lowest values predicted by nuclear models, and nature follows a most conservative scenario, then even probing the IH region would represent a formidable challenge and will demand extraordinary experimental sensitivity [3]. We present a detailed quantitative analysis of how theoretical limitations, including nuclear and particle physics inputs, shape the experimental outlook for 0$\nu\beta\beta$ decay. Our findings highlight that reducing theoretical uncertainties will require both refined nuclear modeling and dedicated measurements, essential for sharpening the predictions of future 0$\nu\beta\beta$ searches.
References:
[1] M. K. Singh, H. T. Wong et al., Exposure-background duality in the searches of neutrinoless double beta decay, Phys. Rev. D 101, 013006 (2020); https://doi.org/10.1103/PhysRevD.101.013006
[2] M. K. Singh, H. B. Li, H. T. Wong et al., Projections of discovery potentials from expected background, Phys. Rev. D 109, 032001 (2024); https://doi.org/10.1103/PhysRevD.109.032001
[3] M. K. Singh, S. Karmakar, H. B. Li, H. T. Wong, et al., Impact of theoretical constraints in the sensitivity estimation for neutrinoless double beta decay, Int. J. Mod. Phys. A (2025); https://doi.org/10.1142/S0217751X25500502Speaker: Dr Manoj Kumar Singh (Institute of Physics, Academia Sinica, Taipei, 115201, Taiwan) -
333
Ultra-Low background germanium spectrometers at the China Jinping Underground Laboratory
Four ultra-low background germanium spectrometers, called GeTHU, have been installed at the first phase of China Jinping Underground Laboratory (CJPL-I) and served for material screening of dark matter and neutrino experiments. Recently, a new multi-detector spectrometer with five germanium detectors has been developed and installed at the second phase of CJPL(CJPL-II) with a minimum detectable activity (MDA) of about 10 μBq/kg level. In addition, another fifteen GeTHU-like spectrometers have been installed at CJPL-II with an MDA of about 1 mBq/kg level. This paper will introduce the ultra-low background germanium spectrometers including shielding design, background characteristics and application to material screening.
Speaker: Jikai Chen (Tsinghua University) -
334
Unlocking the keV frontier: low-energy physics with the CUORE experiment
The CUORE experiment, originally conceived to search for neutrinoless double-beta decay, has proven itself a versatile platform for exploring the broad landscape of rare-event physics. In this talk, we present a comprehensive study of CUORE's sensitivity to keV-scale energy physics - including dark matter interactions and rare nuclear decays. By applying specialized data selection and noise rejection techniques to over 2 tonne·yr TeO$_2$ exposure, we demonstrate effective event reconstruction using energy thresholds as low as 3 keV. We quantify the detector performance across the 988-calorimeter array, exploring how cryogenic conditions, vibrational isolation, and sensor properties influence sensitivity at low energies. These findings validate the use of CUORE-like cryogenic calorimeters as broad-range rare event detectors, spanning from the keV to the MeV scale.
Speaker: Alberto Ressa (INFN-Roma1) -
335
Unveiling the nature of the knee in the cosmic ray energy spectrum with LHAASO results
The knee-like structure around $4~\rm PeV$ is the most striking feature in the cosmic ray energy spectrum, whose origin remains enigmatic. Recently, the Large High Altitude Air Shower Observatory (LHAASO) provided highly precise measurements of cosmic rays in the knee region. Taking into account LHAASO measurements of the all-particle energy spectrum and the mean logarithmic mass, we propose a novel concept of the total logarithmic mass energy spectrum to characterize the knee. The total logarithmic mass energy spectrum is a weighted energy spectrum where flux contributions of different elements are scaled by their respective logarithmic masses, with heavier nuclei assigned greater weights. By virtue of the total logarithmic mass energy spectrum, we find that proton exerts a predominant role in the formation of the knee. Meanwhile, the energy spectrum of light elements is obtained through mixing the all-particle energy spectrum flux and the total logarithmic mass energy spectrum flux according to the specific weight factors. Based on the acquired energy spectrum of light elements, the case of a mass-dependent knee is ruled out with a significance well above 5$\sigma$ and the rigidity-dependent knee feature is revealed. Moreover, an ankle-like structure stemming from the excess of iron is discovered at $9.7 \pm 0.2_{\rm stat} \pm 0.3_{\rm syst}~\rm PeV$ in the total logarithmic mass energy spectrum.
Speaker: Qin-Yi Cheng (IHEP) -
336
Using LHAASO to Search for Ultra-High Energy Gamma-Ray Radiation Enhancement During Crab Nebula Flaring State
The Crab Nebula is an important object of study in gamma-ray astronomy. Since the full array operation of LHAASO-KM2A in July 2021, it has conducted long-term and efficient observations of the Crab Nebula in the very high energy (VHE) range, in the tens of TeV region. We have obtained light curves, energy spectra, and ultra-high-energy photon data from the direction of the Crab Nebula since the full array operation of KM2A. The Crab Nebula exhibits flaring phenomena in the hundreds of MeV to GeV range, first detected by the AGILE satellite of the Italian Space Agency, and later detected multiple times by NASA's Fermi-LAT. Previous observations of these flares by VERITAS and HESS Cherenkov telescopes were made in coordination with Fermi, but no significant flux variation was found in their energy ranges. In our analysis of the long-term light curves from Fermi since the full array operation of KM2A, we detected two flares, in December 2022 and December 2023. During these corresponding time periods, we studied the light curves and energy spectra from KM2A and found no significant flux variations, only providing upper limits on the flux variation.
Speaker: junyang zhang (中国科学院高能物理研究所) -
337
Validating NCQE interaction observables with T2K beam data for DSNB search in Super-Kamiokande
Neutral-Current Quasi-Elastic (NCQE) interactions on oxygen represent a dominant background in the Diffuse Supernova Neutrino Background (DSNB) search at Super-Kamiokande. We validate NCQE background rejection observables by analyzing T2K neutrino beam data, corresponding to 1.76 × 10^{20} protons on target. Three observables, multiple scattering goodness, Cherenkov angle, and reconstructed energy, are evaluated together with neutron capture detection. Neutrons are identified using a neural‑network algorithm, for which an alternative configuration demonstrates the trade-off between detection efficiency and systematic uncertainty. We also assessed how hadron-nucleus interaction models affect both the event observables and the neutron multiplicity. The validated observables and neutron capture results offer key inputs for improving the DSNB search in Super‑Kamiokande.
Speaker: Licheng FENG (Kyoto University) -
338
Vertex reconstruction of shower muons in Larger Liquid Scintillator Detectors using PMT waveforms
In large volume liquid scintillator detectors such as the center detector of Jiangmen Underground Neutrino Observatory (JUNO), the shower muons contribute most of the cosmogenic isotopes, and the isotopes are mainly produced within a few meters around the shower vertex. Cosmogenic isotopes, especially $^{9}$Li/$^{8}$He, are the main background for the JUNO's measurement of reactor neutrinos, so these isotopes need to be labeled and rejected. An effective method is to reconstruct the vertex of the shower muon, and then exclude the events in the space around the shower muon vertex according to the correlation of spatial distribution, thus excluding most of the cosmogenic isotopes at the same time. Compared with non-shower muons, the energy deposition of shower muons in liquid scintillator will cause additional significant peaks in the waveforms of photomultiplier tubes (PMT). This information is used in this paper to study the vertex reconstruction of shower muons. As a result, for a single shower muon within 16~m, the deviation of its reconstructed vertex can be controlled to about 0.4~m, and the resolution of the reconstructed vertex is about 0.7~m.
Speaker: 峻玮 张 (广西大学) -
339
Water Cherenkov Veto for the PandaX-4T Experiment
The water Cherenkov veto detector in the PandaX-4T experiment has been operational since 2024. This poster gives a review of its performance, including the detector operation, calibration, and data analysis. Key results include the measurements of neutron veto efficiency and studies on gamma-ray tagging. Additionally, cosmic ray event selection and reconstruction are discussed. Finally, we describe the tuning of an optical simulation to improve the understanding of detector performance.
Speakers: 予乐 黄 (Shanghai Jiao Tong University), 培源 李 (Shanghai Jiao Tong University), 建琴 许 (Shanghai Jiao Tong University), 曼娜 邓 (Shanghai Jiao Tong University), 熙元 邵 (Shanghai Jiao Tong University), 裕杰 葛 (Shanghai Jiao Tong University) -
340
Wave Front Sensing demodulated with the difference frequency of two phase modulated sidebands in a gravitational wave detector
In a laser interferometer-type gravitational wave telescope, it is necessary to observe by three or more detectors to determine the direction of source of gravitational waves with high accuracy. In the fourth observational run, KAGRA is constructed with PRFPMI consisting of a Michelson interferometer with 3 km Fabry-Perot cavity in both arms, and Power Recycled Cavity.
Wave Front Sensing (WFS) control maintains the optical axis alignment of the interferometer by compensating for relative misalignment with the resonator axis and the incident optical axis. However, many optical axis alignment signals are easily buried in the arm cavity axis signals.
This study proposes a new WFS(PMPM WFS) with the beat signals of two phase-modulated (PM) sidebands that are not injected into the arm cavity. I will present the theoretical validity of PMPM WFS and the measurement results of the PMPM WFS signal at the PRFPMI in KAGRA.Speaker: CHIAKI HIROSE (Niigata university) -
341
Laser isotope separation of 48Ca for the study of neutrinoless double beta decay and the CANDLES project
Neutrinoless double beta decay is a powerful method for verifying Majorana neutrinos. $^{48}$Ca is one of the best candidates because it has the largest $Q$-value of decay (4.27 MeV) and is the target nucleus of the CANDLES project. Although a large number of target nuclei is essential to search for the decay with higher sensitivity, there is no established mass production method for enriched $^{48}$Ca isotopes. Laser isotope separation (LIS) using the deflection method offers the possibility to overcome this difficulty. We have completed proof-of-principle experiments and are developing a prototype system for mass production of $^{48}$Ca by LIS. It consists of 1) a natural calcium atomic beam, 2) a laser for deflection, and 3) a enriched/depleted calcium recovery system, with 1) and 3) installed in a vacuum chamber. For long-term stable production, the following performance is being developed, 1) A well-collimated, high-efficient and intense atomic beam, 2) High intensity laser with narrow line width compared to the natural width of the transition, and 3) A system to efficiently recover enriched and depleted calcium, respectively.
The current status of these developments and an overview of the CANDLES project will be presented.
Speaker: Prof. Izumi OGAWA (University of Fukui)
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252
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On-site registration (start at Saturday 23/08) International Conference Center
International Conference Center
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Plenary session Lufeng Hall
Lufeng Hall
Convener: Haipeng An (Tsinghua University)-
342
Cosmological implications of massive galaxy surveys on dark energy
We investigate whether dark energy deviates from the cosmological constant ($\Lambda$CDM) by analyzing baryon acoustic oscillation (BAO) measurements from the Data Release 1 (DR1) and Data Release 2 (DR2) of DESI observations, in combination with Type Ia supernovae (SNe) and cosmic microwave background (CMB) distance information. We find that with the larger statistical power and wider redshift coverage of the DR2 dataset the preference for dynamical dark energy does not decrease and remains at approximately the same statistical significance as for DESI~DR1. Employing both a shape-function reconstruction and non-parametric methods with a correlation prior derived from Horndeski theory, we consistently find that the dark energy equation of state $w(z)$ evolves with redshift. While DESI DR1 and DR2 BAO data alone provide modest constraints, combining them with independent SNe samples (PantheonPlus, Union3, and the DES 5-year survey) and a CMB distance prior strengthens the evidence for dynamical dark energy. Bayesian model-selection tests show moderate support for dark energy dynamics when multiple degrees of freedom in $w(z)$ are allowed, pointing to increasing tension with $\Lambda$CDM at a level of roughly $3\sigma$ (or more in certain data combinations). Although the methodology adopted in this work is different from those used in companion DESI papers, we find consistent results, demonstrating the complementarity of dark energy studies performed by the DESI collaboration. Although possible systematic effects must be carefully considered, it currently seems implausible that $\Lambda$CDM will be rescued by future high-precision surveys, such as the complete DESI, Euclid, and next-generation CMB experiments. These results therefore highlight the possibility of new physics driving cosmic acceleration and motivate further investigation into dynamical dark energy models.
Speaker: Prof. Gongbo ZHAO (NAOC) -
343
Cosmological collider physics
Particle physics during cosmic inflation can be inferred from the density (galaxy) correlations in our present universe. In particular, the mass of inflationary produced particles appears as a resonance in the correlation. The information about angular momentum, parity and decay width of the inflationary produced particles can be similarly studied. This program is known as the cosmological collider physics. We review cosmological collider physics, the cosmological collider phenomenology of the particle physics standard model, and present related recent progress.
Speaker: Prof. Yi Wang -
344
Axion cosmology
Axion-like particles offer a unified framework to address both dark matter (DM) and dark energy (DE) in cosmology. In this presentation, I will discuss recent advancements in two complementary areas. First, I will explore a quintessence axion model for dynamical dark energy, motivated by recent Baryon Acoustic Oscillation measurements from the Dark Energy Spectroscopic Instrument and Cosmic Microwave Background (CMB) observations. Our analysis identifies a preferred parameter space with a sub-Planckian axion decay constant and a relatively large axion mass, naturally avoiding the quality problem and remaining consistent with theoretical constraints. This model also provides a potential explanation for the recently reported non-zero rotation of the CMB linear polarization angle, emphasizing a broader cosmological implications. Second, I will discuss indirect detection strategies for the QCD axion as a DM candidate. Specifically, we investigate the resonant conversion of axions into photons in the presence of strong magnetic fields, such as those around neutron stars. Radio-telescope observations targeting the Andromeda galaxy have been employed to search for radio transients arising from interactions between neutron stars and dense dark matter clumps, constraining the axion-photon coupling in the mass range of 33 to 42 μeV and offering a novel observational tool to probe axion DM. Based on 2407.13060, 2504.17638 and ongoing work.
Speaker: Luca Visinelli (Università di Salerno & INFN)
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342
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Coffee break International Conference Center
International Conference Center
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Plenary session Lufeng Hall
Lufeng Hall
Convener: Yi Wang-
345
Phenomenological consequences of phase transitions in the early universe
Cosmological phase transitions represent drastic energy-release processes theorized to have occurred in the early universe. These transitions may arise during either the thermal expansion phase of the Big Bang or the inflationary epoch, generating distinctive observational signatures. Key consequences include gravitational waves, large-scale structure, primordial black holes, and primordial non-Gaussianity—phenomena potentially observable today. This talk will comprehensively review recent advances in understanding these phase transitions and their phenomenological implications.
Speaker: Haipeng An (Tsinghua University) -
346
Shedding light on dark matter with gravitational waves: searches in the first part of the fourth observing run of LIGO-Virgo-KAGRA
Dark matter could compose ~80% of all matter in the universe, and yet it is completely invisible to us. Despite decades of experiments designed to detect dark matter, and numerous models for potential dark matter particles, no concrete evidence has been put forward to support the existence of beyond standard-model physics. Because of this, it is worth asking whether approaching the detection of dark matter from a different point of view, that is, via gravitational-wave interferometers, could provide some insight into explaining the origin of dark matter. In this talk, I will discuss searches for dark matter in two forms: ultralight particle dark matter and sub-solar mass primordial black holes. While not designed to search for dark matter, gravitational-wave detectors can robustly probe a variety of dark-matter models simultaneously, without affecting their sensitivity to canonical gravitational-wave sources, and put competitive and sometimes even stronger constraints than those from other experiments designed to search for dark matter.
Speakers: Andrew Miller (Nikhef /Utrecht University), Huaike Guo (中国科学院大学（ICTP-AP）) -
347
High-Energy Gamma-Ray Astronomy: Breakthroughs and Future Prospects from Space- and Ground-Based Observations
Over the past two decades, high-energy gamma-ray astronomy has witnessed revolutionary progress driven by both space- and ground-based observations. Space-borne detectors, epitomized by the Fermi Large Area Telescope (Fermi-LAT), and ground-based facilities, including Imaging Atmospheric Cherenkov Telescopes (IACTs: H.E.S.S., MAGIC, VERITAS) and Extensive Air Shower (EAS) arrays (Tibet ASγ, HAWC), particularly the groundbreaking LHAASO, have dramatically expanded our observational window. This now encompasses the high-energy (HE), very-high-energy (VHE), and ultra-high-energy (UHE) gamma-ray regimes. These observatories have yielded a series of landmark achievements, profoundly transforming our understanding of non-thermal high-energy processes in the Universe and significantly advancing frontiers in particle astrophysics (such as dark matter, cosmic-ray origins, and extreme physics). This talk will systematically review the key technical characteristics and operational status of these major facilities. It will highlight their recent pivotal discoveries (e.g., the confirmation of Galactic PeVatrons), elaborate on their contributions to addressing core scientific questions in particle astrophysics, and conclude with an outlook on future directions in detection technology and scientific research.
Speaker: songzhan chen (Institute of High Energy Physics(IHEP),CAS)
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345
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Lunch Yu’ou Building
Yu’ou Building
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Dark Matter and Its Detection: parallel session 7B Conference Room F2-R2
Conference Room F2-R2
Convener: Masayuki Wada (Astrocent, CAMK PAN)-
348
First Direct Observation of Migdal Effect in Neutral Projectiles
The Migdal effect, a phenomenon in which a nucleus emits an electron following a perturbation, is considered one of the most sensitive methods for detecting sub-GeV dark matter to date. However, for over 80 years, direct observational evidence has been lacking. This presentation will showcase the gas pixel detector we designed for the direct observation of the Migdal effect, along with the experiments and results obtained using neutron beams. We will report the first direct observation of the Migdal effect in neutral beam collisions, as well as the measurement of its cross-section.
Speaker: Difan Yi (中国科学院大学) -
349
Characterization of argon recoils at the keV scale with ReD and ReD+
The Recoil Directionality project (ReD) within the Global Argon Dark Matter Collaboration characterized the response of a liquid argon (LAr) dual-phase Time Projection Chamber (TPC) to neutron-induced nuclear recoils, to measure the charge yield Qy at low-energy. The charge yield is a critical parameter for the experiments searching for dark matter in the form of low-mass WIMPs and measurements in Ar below 10 keV are scarce in the literature. ReD was designed to cover the gap down to 2 keV.
The ReD data taking took place in 2023 at the INFN Sezione di Catania. The TPC was irradiated by neutrons produced by an intense $^{252}$Cf fission source in order to produce Ar recoils in the energy range of interest. The energy of the nuclear recoils produced within the TPC by (n,n') scattering was determined by detecting the outgoing neutrons by a dedicated neutron spectrometer made of 18 plastic scintillators. The kinetic energy of neutrons interacting in the TPC was evaluated event by-event by measuring the time of flight. ReD collected and characterized a sample of nuclear recoils down to 2 keV, thus meeting its design goal.
The ReD effort is being further extended by a new project, ReD+, at INFN Laboratori Nazionali del Sud. ReD+ is designed to reach a threshold of 0.5 keV by using the same conceptual design of ReD and improved components. A dedicated run using a deuterium-deuterium generator is then planned to achieve 0.2 keV.
In this contribution, we describe the experimental setup and present the preliminary results on Qy down to 2 keV from the data analysis of ReD. We also discuss the perspectives to further lower the coverage down to the sub-keV range with ReD+.
Speaker: Luciano Pandola (INFN Laboratori Nazionali del Sud) -
350
Determination of the sensitivity of the DEAP-3600 experiment to supermassive charged gravitinos
Current experiments have not yet led to the discovery of dark matter with particle masses of the order of eV (for axion dark matter) up to the TeV scale (for WIMPs). An unconventional idea is gaining popularity that dark matter may consist at least in part of a rarefied gas of stable gravitinos with masses of the order of the Planck mass and fractional charge. These particles would interact with ordinary matter but could not decay into it.
In this talk I will show that large underground detectors based on noble gas scintillation are perfectly suited for searching for supermassive charged gravitinos and present sensitivity study for DEAP-3600 detector based on dedicated Monte Carlo simulation.
Speaker: Michal Olszewski (AstroCENT) -
351
Electronic Recoils in Xenon Detectors Induced by Solar Neutrinos
Electronic recoil caused by solar neutrinos in multi-ton xenon detectors is a powerful probe of solar physics, and an important background for direct searches of dark matter and double beta decay. Following our previous work [1], we extend our study of recoil energy up to 150 keV, with an improved relativistic random phase approximation (RRPA) and calculations of bound-to-free transitions induced by high multipole operators. The comparison with other simplified methods including free-electron approximation, plane-wave approximation, and independent particle models, will be discussed.
[1] Jiunn-Wei Chen, Hsin-Chang Chi, C.-P. Liu, and Chih-Pan Wu, Phys. Lett. B 774 (2017) 656.
Speaker: CHIH-PAN WU (National Dong Hwa University) -
352
First observation of positron emission decay of Xe-125 in a noble liquid detector from the LUX-ZEPLIN Experiment
We report the first observation of the positron emission process, $^{125}\text{Xe}\rightarrow e^+ + \nu + ^{125}\text{I}$ (Q=$1.6~\mathrm{MeV}$), in a noble liquid detector using post-calibration data from the LUX-ZEPLIN (LZ) detector. We detect this decay and provide an independent measurement of the branching fraction. $^{125}\text{Xe}$ is a short-lived ($\tau_{1/2}\sim 17~\mathrm{h}$) isotope of xenon which can be produced by neutron activation on the stable and naturally abundant $^{124}\text{Xe}$, primarily decaying by electron capture. The positron emission decay mode has been previously indirectly measured through triple coincidence of annihilation and de-excitation gammas, but no direct measurement of the kinetic energy deposited by the emitted positron has been previously made. This analysis shows the ability of LXe TPCs to search for more complex event topologies than the single-scatter expected from dark matter interactions, particularly the higher order decay of $^{124}\text{Xe}$, the two neutrino electron capture with positron emission ($\text{2}\nu\text{EC}\beta^+$).
Speaker: Miguel Hernandez
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348
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Gravitational Waves: parallel session 7 Conference Room F1-R3
Conference Room F1-R3
Convener: Yiqiu Ma-
353
The staus of KAGRA Large-scale Cryogenic Gravitational Wave Telescop
KAGRA gravitational wave telescope in Japan started the 4th international gravitational wave observation(O4) with Advanced-LIGO and Advanced Virgo in May 2023, after repairs, upgrades, and commissioning for 3 years from May 2020. Under the LIGO-Virgo-KAGRA(LVK) O4 scenario, KAGRA restarted its commissioning from July 2023 to upgrade and improve its sensitivity and to rejoin O4 around Spring 2024. However, the magnitude 7.4 Noto Peninsula earthquake severely damaged 10 out of 20 mirror suspension systems, along with other detector components. Recovery efforts began immediately after the earthquake and were completed in July 2024. Thanks to 11 months of dedicated commissioning work, KAGRA achieved a binary neutron star (BNS) range of up to 6.9 Mpc and is officially rejoining O4 in June 2025. In this presentation, we report on the recovery process, upgrades, and commissioning efforts at KAGRA for O4, as well as a portion of the current observational status.
Speaker: Prof. Shinji MIYOKI (Institute for Cosmic Ray Research, The University of Tokyo) -
354
Use of phase sensitive amplifier for the back-action evasion scheme
We present a number of new techniques to utilize a phase-sensitive amplifier to effectively reduce an optical loss in the output readout chain.
Speaker: Kentaro Somiya (Institute of Science Tokyo) -
355
Quantum entanglement for gravitational-wave detectors
Quantum entanglement has recently begun to play an increasingly important role in astrophysical observations. Innovative techniques such as quantum steering, entanglement swapping, and quantum teleportation are opening new possibilities for precision measurements that surpass classical limits.
In this presentation, we provide a theoretical overview of how quantum entanglement can be applied to gravitational-wave detectors. We also discuss the potential for novel applications of entanglement through entanglement swapping between optical fields and the mechanical mirrors that constitute the interferometric detectors.
Speaker: Mr Yohei Nishino (University of Tokyo) -
356
Space-based optical lattice clocks as gravitational wave detectors
We investigate the sensitivity and performance of space-based Optical Lattice Clocks (OLCs) in detecting gravitational waves, in particular the Stochastic Gravitational Wave Background (SGWB) at low frequencies $(10^{-4}, 1) \rm Hz$, which are inaccessible to ground-based detectors. We first analyze the response characteristics of a single OLC detector for SGWB detection and compare its sensitivity with that of Laser Interferometer Space Antenna (LISA). Due to longer arm lengths, space-based OLC detectors can exhibit unique frequency responses and enhance the capability to detect SGWB in the low-frequency range, but the sensitivity of a single OLC detector remains insufficient overall compared to LISA. Then, as a preliminary plan, we propose a novel method for space-based OLC detectors that can significantly improve the signal-to-noise ratio (SNR) by utilizing the cross-correlation between two of them. This method leverages the uncorrelated origins but statistically similar properties of noise in two detectors while the SGWB signal is correlated between them, thus achieving effective noise suppression and sensitivity enhancement. Our results indicate that the cross-correlation technique can improve the sensitivity by approximately an order of magnitude compared to a single OLC detector configuration, and even would surpass current detection systems such as LISA in the full-band detection capability of SGWB.
Speaker: Bo Wang (中国科学技术大学) -
357
Fundamental Quantum Limits for Detecting Ultra-high Frequency Gravitational Waves
The ultrahigh-frequency (above 10 kHz) gravitational waves (GW) window provides a unique opportunity to detect primordial GWs, free from astrophysical foregrounds that dominate lower frequencies. A stochastic GW background in this range is generically predicted from cosmological phase transitions and topological defects associated with grand unification and other ultra-high energy theories. We establish a universal quantum limit framework for various detection schemes, setting a fundamental bound on GW detectability. Our analysis reveals that backgrounds in the kHz – MHz range are in principle observable, whereas higher-frequency signals lie below the quantum limit. These results offer theoretical guidance for future detector designs and open new avenues for probing early universe physics.
Speaker: Xinyao Guo
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353
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High-Energy Astrophysics and Cosmic Rays: parallel session 7 Conference Room F1-R2
Conference Room F1-R2
Convener: Silvia Crestan (INAF-IASF Milano)-
358
Recent Scientific Results from VERITAS
VERITAS is a ground-based gamma-ray observatory designed to detect astrophysical very-high-energy (VHE; 100 GeV < E < 30 TeV) gamma rays. It consists of an array of four 12-meter imaging atmospheric Cherenkov telescopes (IACTs) located in southern Arizona, USA. Since VERITAS was placed into operations nearly two decades ago, the observatory has played a central role in investigating both Galactic and extragalactic VHE phenomena. Its observations include, but are not limited to, supernova remnants, pulsar wind nebulae such as MGRO J1908+06 and pulsar halos, X-ray binaries, as well as extragalactic sources including the starburst galaxy M82, active galactic nuclei such as the nearby elliptical galaxy M87, blazars such as 1ES 1028+511, radio galaxies, and fast radio bursts. The facility has also contributed significantly to the field of multimessenger astrophysics, with results ranging from constraints on dark matter from dwarf spheroidal galaxies to target-of-opportunity searches to astrophysical neutrinos, such as TXS 0506+056, and follow-ups of gravitational wave events. This presentation will showcase recent developments from the VERITAS science program and highlight key discoveries.
Speaker: Weidong Jin (University of California, Los Angeles) -
359
Detection of extragalactic sources and Transients from LHAASO-WCDA
Key sources of very high-energy (VHE) gamma rays include extragalactic objects such as blazars, gamma-ray bursts (GRBs), and other intriguing transient events. Investigating these targets is essential for gaining critical insights into various astrophysical phenomena, including black hole accretion, particle acceleration, and the dynamics of explosive events.
The Large High Altitude Air Shower Observatory (LHAASO), located in China, is a multi-purpose facility designed to detect cosmic rays and gamma rays in the energy range from a few hundred GeV to a few hundred PeV. As one of three sub-arrays comprising LHAASO, the Water Cherenkov Detector Array (WCDA). The wide field of view, high duty cycle, and high sensitivity of LHAASO-WCDA provide an ideal platform for capturing these flaring phenomena, contributing to a deeper understanding of their origins and characteristics. In this work, I will present the extragalactic sources detected by LHAASO-WCDA, along with a preliminary catalog of these sources. Details regarding transient event handling, including the monitoring framework, analysis pipeline, and results, will also be included.Speaker: min zha -
360
Particle acceleration beyond the synchrotron burnoff limit in gamma-ray binary systems
Gamma-ray observations can constrain particle acceleration in astrophysical sources only when combined with realistic emission scenarios. A key question is whether the radiation originates from relativistic electrons or protons. While several criteria exist to distinguish between leptonic and hadronic origins, they often remain inconclusive at ultra-high energies. For instance, the synchrotron counterparts of leptonic emission may peak in the MeV band, where sensitivity is limited, while the detection of neutrinos at expected flux levels remains elusive. In such cases, arguments based on maximum attainable particle energies become critical. Recent ultra-high-energy observations of binary systems indicate that, under certain conditions, electrons can overcome the synchrotron cooling limit. This mechanism, if confirmed, may also operate in other sources with ultrarelativistic outflows, such as pulsar wind nebulae and gamma-ray bursts.
Speaker: Dmitriy Khangulyan (IHEP) -
361
Gamma-ray detection consistent with a young stellar object
Jets from protostellar have recently been reported to have the capability to accelerate particles to relativistic energy, emitting gamma photons that can be detected by the Fermi-LAT. Some protostellars have also been reported to have observed non-thermal jet lobes in radio band, confirming the presence of non-thermal processes within the jets. We analyzed 16 years of Fermi-LAT data one protostellar object which is relatively close to the Earth with non-thermal jets. We have detected an excess of gamma radiation near this protostellar, and discussed the possible origin of the gamma ray emission.
Speaker: P. H. Thomas Tam (Sun Yat-sen University) -
362
HAWC Study of HESS J1857+026 for a Multiwavelength Study Effort
The High Energy Stereoscopic System (H.E.S.S.) collaboration reported the emission of two sources HESS J1857+026 and HESS J1858+0200 with no known counterparts. The High Altitude Water Cherenkov (HAWC) collaboration confirmed the detection in their 3HWC catalog with an association to 3HWC J1857+027. We present a multi-source fitting analysis of the HESS J1857+026 region as part of a multi-wavelength study effort to uncover its emission mechanisms. Using ~2860 days of Pass 5 observations from the HAWC observatory, we now resolve the emission from both sources in the region beyond tens of TeV and find a cutoff in the emission for HESS J1857+026 for energies beyond ~30 TeV.
Speaker: Ramiro Torres Escobedo (上海交通大学)
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358
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Neutrino Physics and Astrophysics: parallel session 7A North Hall #1
North Hall #1
Convener: Lukas Berns-
363
The SAND detector of the DUNE experiment
The Deep Underground Neutrino Experiment (DUNE) is a next-generation neutrino oscillation long-baseline experiment designed to measure the neutrino mass ordering, the CP-violating phase in the lepton sector of the Standard Model and to improve the precision on key parameters that govern neutrino oscillations. The System for on-Axis Neutrino Detection (SAND) at the DUNE Near Detector complex is designed to monitor the beam on-axis, control systematic uncertainties for the oscillation analysis, precisely measure neutrino cross sections, and perform short-baseline neutrino physics studies.
SAND will exploit the existing KLOE electromagnetic calorimeter made of alternating lead/scintillating fiber layers that will work with a 0.6 T superconducting magnet, both refurbished from the KLOE experiment. The Straw Target Tracker (STT) occupies most of the internal volume. It is composed of alternating planes of thin graphite/polymer targets and straw tube planes, providing multiple nuclear targets for the measurement of $\nu$-p and $\nu$-C cross-sections. A 1-ton active target for the $\nu$ -Ar interactions, called GRAIN, is located in front of the STT and is designed to image neutrino interactions using scintillation light produced in Ar by charged particles. In this talk, the current status of the detector and its performance will be discussed.Speaker: Denise Casazza (INFN Sezione Ferrara - Università di Ferrara) -
364
The Short-Baseline Near Detector at Fermilab
The Short-Baseline Near Detector (SBND) is a Liquid Argon Time Projection Chamber (LArTPC) neutrino detector located 110 meters downstream of the target in the Booster Neutrino Beam (BNB) at Fermilab. SBND is characterized by superb imaging capabilities thanks to its low-noise cold electronics and an advanced photon detection system. Because of its proximity to the target, SBND will record around 2 million neutrino interactions per year which enable a rich program of neutrino interaction measurements and novel searches for physics beyond the Standard Model (BSM). In addition, SBND is the near detector of the SBN sterile neutrino program, and will precisely constrain the flux and neutrino-argon cross-section systematic uncertainties as part of a world-leading search for eV-scale sterile neutrino oscillations. This talk will discuss the first data, current status, and physics reach of SBND.
Speaker: Thomas Wester (University of Chicago) -
365
Commissioning of the JUNO detector
The Jiangmen Underground Neutrino Observatory (JUNO) is a multi-purpose 20-kiloton liquid scintillator detector set to begin data-taking this year. The experiment aims to have world-leading sensitivity to the neutrino mass ordering and make sub-percent precision measurements of oscillation parameters Δm_31^2, Δm_21^2, sin^2(θ_12). These goals hinge on precisely resolving the fine oscillation structure in the antineutrino energy spectrum of nuclear reactors ~52.5km away. For this, a world-leading energy resolution is required, alongside low background rates. To prepare for operation, following the completion of detector construction, JUNO underwent its commissioning phase. This is a two-stage process, beginning with a full fil of the detector’s central cavity with pure water, followed by the gradual replacement of the water in the inner vessel with the final liquid scintillator mixture. This talk will present an overview of the detector’s commissioning, highlighting key procedures and preliminary performance evaluations carried out during both the pure water and liquid scintillator phases, essential for the experiment’s future smooth running.
Speaker: Iwan Morton-Blake (Tsung-Dao Lee Institute / Shanghai Jiao Tong University) -
366
Status and Prospect of JUNO-TAO
Taishan Antineutrino Observatory (TAO) is a satellite experiment of JUNO. It consists of a ton-level liquid scintillator detector at around 44 meters from a reactor core of the Taishan Nuclear Power Plant. It detects reactor antineutrinos by inverse beta decay (IBD). Silicon photomultipliers which have ~95% coverage and ~50% photon detection efficiency are used to collect photoelectrons, resulting in the light yield is ~4500 photoelectrons per MeV. Dark noise of SiPM is suppressed by orders of magnitude by cooling the detector down to -50 degrees. The main goal of TAO is to get the precise energy spectrum of reactor antineutrinos with very high energy resolution (<2% at 1 MeV). It will deliver a reference energy spectrum for JUNO to reduce the impact from the reactor antineutrino flux and spectrum model uncertainties, and provide a benchmark to nuclear databases. In addition, TAO can also search for light sterile neutrinos with a mass scale around 1 eV and help to verify of the technology for reactor monitoring and safeguard.
This talk will show the latest status and prospect of TAO detector.Speaker: Ruhui Li (IHEP) -
367
Development of the calibration sources for the JUNO experiment
The Jiangmen Underground Neutrino Observatory (JUNO), located in southern China, is the world’s largest underground liquid scintillator-based neutrino experiment. It aims to study neutrinos from various sources, including reactors, the atmosphere, the Sun, the Earth, and supernovae. The central detector comprises a 20-kton liquid scintillator volume, equipped with over 17,000 20-inch and more than 25,000 3-inch photomultiplier tubes. To achieve JUNO’s unprecedented target energy resolution of 3% at 1 MeV — critical for determining the neutrino mass ordering — as well as to support a wide range of physics goals spanning energies from several tens of keV to beyond 10 GeV, a variety of calibration sources have been developed. These include low-energy radioactive sources such as $^{226}$Ra and $^{241}$Am, a repeatedly regenerated $^{18}$F source by irradiating fluoride with fast neutrons, as well as an optical calibration system with tunable intensity over four orders of magnitude. These sources are planned to be deployed at multiple positions within the detector using the calibration source deployment systems. In this presentation, I will discuss the design and development of these customized calibration sources for the JUNO experiment.
Speaker: Akira Takenaka (Tsung-Dao Lee Institute, Shanghai Jiao Tong University)
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363
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Neutrino Physics and Astrophysics: parallel session 7B North Hall #2
North Hall #2
Convener: Giorgio Gratta-
368
Update on the ECHo Experiment
The ECHo experiment measures the energy spectrum of the Electron Capture decay in Holmium-163 to determine the effective mass of the electron neutrino. Arrays of metallic magnetic calorimeters enclosing the $^{163}\textrm{Ho}$, operated at temperatures around $20 \textrm{mK}$, are used for the high energy resolution measurement of the spectrum. In the first phase of the experiment, ECHo-1k, a $^{163}\textrm{Ho}$ spectrum with more than 200 million events has been acquired with detectors enclosing an average activity of 0.7 Bq. The analysis of this spectrum set the current most stringent limit on the effective electron neutrino mass of $19 \textrm{eV}$ at $95\% \textrm{C.L.}$.
The success of the first phase of the ECHo experiment sets the basis for the development of the next phase with the aim of acquiring more than $10^{13}$ $^{163}\textrm{Ho}$ events and, with that, be able to achieve sub-eV sensitivity for the determination of the effective electron neutrino mass. The necessary upgrade of the hardware and the challenges in data reduction and analysis of the spectrum will be presented.Speaker: Raghav Pandey (Kirchhoff Institute for Physics, Heidelberg University) -
369
Status of the Ptolemy project
The Ptolemy experiment is designed to detect the cosmic neutrino background, believed to have formed roughly one second after the Big Bang, as predicted by the Standard Cosmological Model. Given the extremely low energy of these neutrinos, their detection is feasible through neutrino capture on beta-unstable isotopes, which do not require an energy threshold. Tritium embedded in a carbon-based nanostructure stands out as a strong candidate due to its favorable cross-section and low endpoint energy. To facilitate this detection, the Ptolemy collaboration plans to integrate a solid-state tritium source with an innovative compact electromagnetic filter based on dynamic transverse momentum cancellation. This system will be paired with a preliminary event-triggered radio-frequency preselection. To support the development of the full-scale detector, a prototype demonstrator is currently being assembled and will undergo testing at the Laboratori Nazionali del Gran Sasso (LNGS). This prototype will help address key technical challenges of the experiment and has the potential to measure the neutrino mass with a competivie sensitivity.
Speaker: Dr Nicola Rossi (LNGS-INFN) -
370
The first neutrino mass measurement of HOLMES experiment
The determination of the absolute neutrino mass scale remains a fundamental open question in particle physics, with profound implications for both the Standard Model and cosmology. The only model-independent method for measuring the neutrino mass relies on the kinematic analysis of beta decay or electron capture (EC) decay, assuming only momentum and energy conservation. Embedding the radioactive source inside the detector ensures that all the energy is measured except the fraction carried away by the neutrino, minimizing the systematic uncertanties. Such calorimetric approach is chosen by the HOLMES experiment.
The HOLMES experiment investigates the EC decay of $^{163}$Ho using an array of ion-implanted transition-edge sensor (TES) microcalorimeters. These superconducting devices operate in the transition region between resistive and superconducting states at temperatures around 100 mK. Each TES is coupled to an $^{163}$Ho implanted gold absorber. The temperature rise following an interaction is proportional to the deposited energy. The readout system is based on microwave SQUID Multiplexing ($\mu$MUX), enabling the simultaneous monitoring of multiple detectors with minimal cabling.
During the first phase, Holmium was successfully implanted into an array of 48 detectors, with an activity ranging from tens of mBq to 0.6 Bq, with an average value of 0.27 Bq, constituting the first prototype of the final detector system. The total activity was approximately 15 Bq. Two physics runs, each lasting two months, produced a high-statistics calorimetric spectrum of $^{163}$Ho. Data-taking periods ranged from two to five consecutive days, with a duty cycle of 82\% and a discarded event rate below 1\%. HOLMES achieved an average energy resolution of 6 eV FWHM.
We present the most stringent bound on electron neutrino mass obtained with a scalable low
temperature microcalorimeter array by the HOLMES experiment. Over two months, with a total of $7 \times 10^7$ decay events, we set a Bayesian upper bound on the effective electron neutrino mass of $m_{\beta} < 27$ eV/c$^2$ at 90\% CI.The results on the neutrino mass limit confirm the feasibility of $^{163}$Ho calorimetry for next-generation neutrino mass experiments and highlight the potential of a TES-based approach to push the sensitivity of direct neutrino mass measurements beyond the current state of the art. The scalability of this technique enables larger arrays with enhanced statistics, paving the way for sub-eV sensitivity. During the next phase of the experiment we aim to scale up the detector arrays, optimize the readout, and enhance the implantation efficiency.
Speaker: Dr Sara Gamba (University of Milano Bicocca, INFN) -
371
Technologies for a Future Neutrino Mass Experiment with Tritium
Currently, the best limits on the neutrino mass from the direct measurements are obtained by the KATRIN (KArlsruhe TRItium Neutrino) experiment, giving an upper limit on the mass of electron anti-neutrino of 0.45 eV (KATRIN Collaboration, Science 388, 180 (2025)). Towards the end of this year, KATRIN will reach its desired goal of 1000 days of measurement, allowing the electron anti-neutrino mass to be constrained to a value in the vicinity of 0.3 eV. Going beyond this limit, and eventually excluding the inverted mass ordering, will be the task of future neutrino mass experiments.
Achieving these ambitious goals will require a paradigm shift in the experimental approach, necessitating development of new and scalable technologies. In particular, a combination of an ultra-high resolution differential detection method together with a high-luminosity atomic tritium source shows a promising path forward.
Building upon the success of the KATRIN experiment, in the following years we plan to develop a quantum sensor array and atomic tritium demonstrators, making use of the existing KATRIN and TLK (Tritium Laboratory Karlsruhe) infrastructure.
In this talk, we present the status of our R&D efforts towards development of these new technologies as a basis for the next generation neutrino mass experiment with tritium, the so called KATRIN++. We will show the results of our first measurement campaigns with the $\mathrm{^{83}Rb/^{83m}Kr}$ radioactive source, and discuss our plans for the proof-of-principle measurements of the tritium $\beta$-spectrum with an ultra-high resolution cryogenic microcalorimeters.Speaker: Neven Kovac (Institute for Astroparticle Physics- Karlsruhe Institute of Technology) -
372
Helicity-changing decays of relic neutrinos and detections in PTOLEMY-like experiments
We calculate the decay rate of a massive neutrino to a lighter one and a massless Nambu-Goldstone boson $\nu_i \to \nu_j + \phi$ in the general case, where the individual helicities of parent and daughter neutrinos are specified. Such invisible decays of cosmological relic neutrinos are studied and the impact on the capture rates in the PTOLEMY-like experiments is analyzed. We find that the helicity-changing decays of Dirac neutrinos play a crucial role, while those of Majorana neutrinos have no distinct effects.
Speaker: Jihong Huang (IHEP)
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368
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Underground Laboratories: parallel session 7 North Hall #3
North Hall #3
Convener: Yihui He (Soochow University)-
373
Research progress on new silicon drift detector for X-ray detection
Silicon drift detectors have important applications in electron microscopes (SEM), X-ray fluorescence spectroscopy (XRF), synchrotron radiation sources, and particle detection. We have systematically constructed a new type of silicon drift detector using innovative principles, structures, and processes. This report found that the doping concentration and doping depth of the anode of the silicon drift detector have an important influence on the collection of drift electrons. We increased the doping concentration of the anode of the silicon drift detector from 1E18/cm-3 to 1E20/cm-3, and the doping depth from 50nm to 1000nm. It can be seen that the concentration of electrons collected at the anode has increased by more than 5 times, which is of great significance for improving the counting rate and detection efficiency.
Speaker: Prof. Rui Jia (Xi’an Jiaotong University) -
374
R&D of the microchannel plate photomultiplier tubes
The microchannel plate photomultiplier tube is an important device for particle and nuclear detection due to its high time resolution, resistance to irradiation, strong magnetic fields and irradiation. The timing performance, lifetime, dynamic range, and resistance to strong magnetic fields are carefully studied and enhanced. A series of MCP-PMTs, including the fast MCP-PMT, gated MCP-PMT, long life MCP-PMT, large dynamic range MCP-PMT and position-sensitive MCP-PMT, has been developed in XIOPM and applied to laser fusion and strong pulsed radiation field measurement experiments, as well as serving Super Tam Charm Facility.The concept of a hybrid MCP-PMT with tens of µm position resolution will be introduced as well.
Speaker: 萍 陈 -
375
Prototype Testing for TRIDENT: In-Situ Performance of Multi-PMT Optical Modules
The TRopIcal DEep-sea Neutrino Telescope (TRIDENT) is a next-generation neutrino telescope to be constructed 3.5km deep in the “Hai-Ling Basin” of the South China Sea. The detector aims to have world-leading sensitivity to high-energy astrophysical neutrinos of all flavours, instrumenting multiple cubic kilometres of seawater with advanced photon-detection technology. TRIDENT features innovative Hybrid Digital-Optical-Modules (hDOMs) which integrate multiple small PMTs and SiPMs for efficient and precise Cherenkov light detection. In preparation for the deployment of its first 10 strings in TRIDENT Phase-1, a single string prototype named TRIDENT-Explorer(T-REX) 2024 was deployed at the future detector’s site. The string was equipped with multi-PMT DOMs, to assess the performance of a preliminary hDOM in dynamic deep-sea conditions. Month-long operation of the systems enabled continuous monitoring of the optical background and provided important reliability validation data for the detection units in a complex underwater environment. This work presents the design and in-situ performance parameters of the prototype mDOMs. Long-term optical background measurements are also presented.
Speaker: Fuyudi Zhang (TDLI) -
376
Development of Ge detectors at THU for rare event detection
Germanium detectors are widely used in rare event detection and low background facility. In this report, some new progress will be presented, including novel electrode design, new PSD method, electronics, long term operation in cryogenic liquid. Some new electrode fabrication method and segmented detectors developed at THU will also be discussed.
Speaker: Yang Tian (Tsinghua University) -
377
Progress of Domestic High-Purity Germanium Crystals growth and detector fabrication
High Purity Germanium Detectors，HPGe is popular in nuclear plant, environment monitor and nuclear chemistry analysis because of its high energy resolution and high detection efficiency. This study aims to fabricate and test HPGe detector that is qualified for commercial purpose. The detector is made from domestic growth 13N crystal and the contact is made by Li diffusion and B ion implantation. The surface of the intrinsic surface is protected by sputtered SiN after chemical passivation. After encapsule the detector is cooled down to -175℃. The leakage current is in good condition 27pA@2900V. Then its spectrum performance is tested using 60Co. The energy resolution of 1.33MeV 60Co is 1.89keV. Other progress are also included.
Speaker: Wei Zhang
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373
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Coffee break International Conference Center
International Conference Center
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Gravitational Waves: parallel session 8 Conference Room F1-R3
Conference Room F1-R3
Convener: Bram Slagmolen-
378
New dark matter production mechanism and the gravitational wave signals
Since the WIMP dark matter from the freeze-out mechanism is not favored by current dark matter direct search, we explore new dark matter production mechanism and the possible gravitational wave signals.
Speaker: Fa Peng Huang (Sun Yat-sen University) -
379
Gravitational wave spectrum from metastable cosmic string network and the delayed scaling scenario
Recent observations by pulsar timing arrays (PTAs) such as NANOGrav, EPTA, PPTA, and CPTA suggest the presence of nanohertz stochastic gravitational wave background (GWB), which may be a hint for new physics. Among several possible sources, those from metastable cosmic string would be attractive since the spectral tilt of the GWB can be easily consistent with those suggested in PTAs. However, there are two issues in this scenario; i) it is inconsistent with the non-observations of the stochastic GWB at LVK, ii) it needs fine-tuning in the highest temperature of the Universe to have cosmic string formation without monopole formation. In this talk, I will discuss if cosmic strings are formed during inflation after sufficient dilution of monopoles, they start emitting gravitational waves at relatively later time to avoid the LVK bound. I also show the numerical and analytic evaluation of the shape of the whole GWB spectrum and its parameter dependence.
Speaker: Kohei Kamada (Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences) -
380
The Equilibrium Spectrum of Stochastic Gravitational Wave Background and Its Role in Cosmic Evolution
The properties of the stochastic gravitational wave background are crucial for our understanding of cosmic evolution. With the release of data from major pulsar timing arrays, the existence of an extremely low-frequency stochastic gravitational wave background has been widely acknowledged. In this work, based on the theory of general relativity and stochastic dynamics, we have established the fluctuation and dissipation mechanisms of matter in the presence of a classical stochastic gravitational wave background, as well as the fluctuation-dissipation relation. Through a generalized Langevin model, we demonstrate the constraints imposed by the matter equilibrium assumption on the strain power spectrum function of the stochastic gravitational wave background, which is essentially a result of the backreaction of matter on the stochastic background. By fitting our derived strain power spectrum (equilibrium spectrum) to the pulsar timing array data released by NG15, we obtain a Bayesian factor of 48±3.8 (relative to SMBHB), which provides strong evidence for the existence of the equilibrium spectrum.
Speaker: Manjia Liang (Institute of Mechanics, Chinese Academy of Sciences) -
381
Detecting Gravitational Waves from Cosmic Phase Transitions in Space
This presentation explores the detection and analysis of stochastic gravitational wave backgrounds (SGWB) originating from first-order cosmological phase transitions, with a focus on the sound wave contributions. It begins by introducing the relevant detector configurations, including space-based interferometers like LISA and Taiji, and the construction of AET channels to extract clean gravitational wave signals. Simulated data are generated in both time and frequency domains, incorporating realistic noise and signal models. A comprehensive statistical analysis framework is developed, combining likelihood functions, Fisher matrix forecasts, and MCMC sampling to extract and constrain physical parameters. Finally, the talk connects the phenomenological gravitational wave parameters to the underlying extended Standard Model (xSM) parameters, demonstrating how SGWB observations can inform particle physics beyond the Standard Model.
Speaker: Qingyuan Liang (ICTP-AP) -
382
Compact Four degree-of-freedom Seismometer with Capacitive Readout
Seismic noise in both translational and angular degree-of-freedom poses significant challenges to high-precision measurements. To mitigate low-frequency seismic noise coupling, active vibration isolation platforms have been developed, with the combination of low-noise and single or multiple degree-of-freedom seismometers play a critical role. This paper presents the design and performance evaluation of a four degree-of-freedom seismometer based on an single flexure inverted pendulum within a $15\,\rm cm$ cube. The seismometer employs differential capacitive sensing scheme to readout test mass motion, similar to which used in the LISA gravitational-wave detector. Two sensing modes are employed: 2D mode and 4D mode. In 2D mode, translational motions are measured, with an optimal translational noise floor of $2 \times 10^{-10}\,\mathrm{m/s^2/\sqrt{Hz}}$ around $1\,\rm Hz$. In 4D mode, a single seismometer can measure both translational and angular motion, whereas two spatially separated XYZ seismometers would typically be employed. However, the angular sensitivity is limited by the compactness of seismometer and the intrinsic stiffness of flexure, which leaves for future optimization.
Speaker: Yulin Xia
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378
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Dark Matter and Its Detection: parallel session 8B Conference Room F2-R2
Conference Room F2-R2
Convener: Junhui Liao-
383
Search for Dark Matter ALPs Through Photon Couplings in Atomic Systems
Axion-like particles (ALPs) have emerged as a compelling portal to the dark sector, offering unique experimental signatures through their coupling to photons. In recent years there has been remarkable progress in the physics of axions and ALPs in several directions. In this work, we investigate the feasibility of detecting dark matter ALPs via inverse Primakoff (IP) scattering process, where ALPs convert into photons through interactions with atomic electromagnetic fields. The primary contribution of our study is two-fold: firstly, we perform detailed cross-section calculations for IP inelastic channels of atomic excitation and ionization, incorporating realistic atomic charge and current distributions using state-of-the-art many-body atomic physics methods. Secondly, expanding the parameter space in ($m_{a}$, $g_{a\gamma\gamma}$) for laboratory-based investigations into DM-ALPs. We derive experimental sensitivities at $90\%$ CL using data from the surface-level TEXONO [1, 2] experiment using high-purity germanium detector and the underground XENONnT [3] experiment using liquid xenon, both featuring low-threshold electromagnetic detectors. Dark matter ALP detection is constrained by the requirement of ALP stability over cosmological timescales. The lifetime of ALPs has to be longer than the age of the Universe in order for the dark matter ALP to reach and be observable in terrestrial experiments. This leads to the finding that part of the ($m_{a}$, $g_{a\gamma\gamma}$) parameter space is not accessible by the current direct experimental searches. However, we outline a path forward: future low-threshold, high-exposure detectors could extend sensitivity up to MeV-scale ALPs by exploiting the inelastic IP process. This work has been published in Physical Review D (Ref [4]) and it opens new laboratory-based opportunities to explore the ALP dark matter landscape beyond the reach of traditional searches.
References
[1] H. T. Wong et al. (TEXONO Collaboration), Phys. Rev. D 75, 012001 (2007).
[2] L. Singh et al. (TEXONO Collaboration), Phys. Rev. D 99, 032009 (2019).
[3] E. Aprile et al. (XENON Collaboration) Phys. Rev. Lett. 129, 161805 (2022).
[4] C.-P. Wu, C.-P. Liu, Greeshma C et al., Phys. Rev. D 108, 043029 (2023).Speaker: Ms Greeshma Chandrabhanu (Institute of Physics, Academia Sinica, Taipei 11529, Taiwan & Department of Physics, Central University of South Bihar, Gaya 824236, India.) -
384
Cryogenic Underground TEst facility at SNOLAB: Infrastructure and Latest Results
Cryogenic technologies are used for a variety of applications in particle, nuclear and quantum physics. The Cryogenic Underground TEst facility (CUTE) at SNOLAB provides a low background, vibration-isolated environment for testing and operating these devices. The experimental stage of CUTE can reach a base temperature of 12 milliKelvin, and can hold a payload up to 20 kg. Over the past years the facility has successfully operated a SuperCDMS High Voltage detector tower, a few sub-eV resolution SuperCDMS HVeV (High-Voltage with eV resolution) detectors, with an ongoing project aiming to probe the impact of cosmic rays on qubit coherence times. This talk will present the CUTE facility as well as the recent results from the above-mentioned projects.
Speaker: Ziqing Hong (University of Toronto) -
385
Status and Prospects of Kamioka Cryolab
Recently, there has been an increasing interest in searching for low-mass dark matter. To address this new direction, a new experimental setup for low-mass dark matter searches is currently being commissioned at the Kamioka Underground Laboratory. A dilution refrigerator has been installed underground, and gamma and neutron shielding is under construction. Ambient gamma and neutron levels have been measured and a Geant4 simulation model has been constructed to predict experimental background rates with this setup. Multiple experiments are under preparation for g-yr level dark matter searches starting in late 2025, including superconducting targets with optical TES sensor readout and a test underground run of a superfluid helium payload. In this talk, a status update will be given and future prospects will be briefly discussed.
Speaker: Suerfu Burkhant (High Energy Accelerator Research Organization (KEK)) -
386
A Tonne-scale Demonstrator of The DarkSide-20k Inner Detector
The DarkSide-20k experiment represents the latest phase of the Global Argon Dark Matter Collaboration, leveraging expertise from previous argon-based detectors. This effort is focused on constructing a dual-phase liquid argon time projection chamber (LAr-TPC) that will deploy 100 tonnes of underground argon outfitted with silicon photomultiplier (SiPM) arrays for precise light detection. Currently in the construction phase, the external cryostat is being installed at the Laboratori Nazionali del Gran Sasso (LNGS) in Italy. This presentation will provide an overview of the DarkSide TPC, highlight its key design elements and provide results from ongoing prototypes to validate the design.
Speaker: Ako Jamil (Princeton University) -
387
Veto Development for the PandaX Experiment
PandaX is a dark matter and neutrino experiment based at the China Jinping Underground Laboratory. It employs a dual-phase liquid xenon TPC to search for dark matter particles and study neutrinoless double-beta decay. Neutron and gamma background events in these searches can be mitigated using an external veto detector. This presentation will provide an update on the operational status of the water Cherenkov veto in the PandaX-4T experiment. Additionally, the research and development efforts for a cold liquid scintillator veto, designed for the next-generation PandaX-xT experiment, will be introduced. Finally, we will present plans to instrument the 4 kton water pit, where the TPC is submerged, with 3-inch PMTs to detect cosmic muons and atmospheric neutrinos.
Speaker: Junting Huang (Shanghai Jiao Tong University) -
388
Spectral Features of Argon Light Emission for Next-Generation Rare Event Detectors
We present recent advances in the spectroscopic characterization of scintillation and electroluminescence (EL) light in gaseous argon. A detailed investigation was conducted using a wavelength-sensitive time projection chamber to study light emission in two spectral regions: the well-known second continuum at 128 nm, and a broader, softer component spanning the far and mid-ultraviolet range (160–325 nm), commonly associated with the third continuum.
Time-resolved measurements with α and β sources in gaseous argon revealed that this fast, soft-UV component—characterized by a decay time of approximately 5 ns—can contribute up to 20% of the total photon yield. Importantly, its intensity shows little dependence on electric field strength or gas pressure. In addition, we provide new spectroscopic evidence of this component in EL light produced by ionization electrons accelerated in a high-field region, using radioactive sources.
These findings challenge the long-standing assumption of monochromatic photon emission in argon and indicate that spectral information may play a more significant role than previously thought in noble gas detectors. This insight opens new avenues for particle identification and background rejection, and may enhance the design and performance of next-generation detectors for dark matter and neutrino experiments.
In this talk, we will present the current status, key results, and future prospects for the spectroscopic analysis of scintillation light in liquid argon.
Speaker: Roberto Santorelli (CIEMAT) -
389
Low-energy Yttrium-Beryllium calibration in XENONnT
Characterizing low-energy, keV-range nuclear recoils near the detector threshold is a crucial recipe for the recent highlights from the XENONnT experiment — for accurately measuring the solar Boron-8 neutrino via coherent elastic neutrino-nucleus scattering (CEvNS) and searching for light dark matter particles. In this talk, we will present the first calibration campaign using an Yttrium-Beryllium photoneutron source in the XENONnT experiment. From the nuclear recoil events induced by this 152 keV neutrons source, we extracted the light (charge) yield for liquid xenon at our field strength of 23 V/cm between 0.56 (0.62) keV and 5.0 keV. This talk will cover aspects such as source design, simulation and data analysis.
Speaker: Shengchao Li (西湖大学 Westlake University)
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383
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High-Energy Astrophysics and Cosmic Rays: parallel session 8 Conference Room F1-R2
Conference Room F1-R2
Convener: P. H. Thomas Tam (Sun Yat-sen University)-
390
Early Science with the First Large-Sized Telescope (LST-1)
The Large-Sized Telescopes (LSTs) constitute the largest class of instruments within the upcoming Cherenkov Telescope Array Observatory. Four LSTs are being constructed at the Observatorio del Roque de los Muchachos on La Palma, Canary Islands, Spain. Each telescope features a 23-meter reflector and is optimized for observations at energies below 100 GeV. The first Large-Sized Telescope (LST-1) was inaugurated in October 2018 and is currently engaged in scientific observations of galactic, extragalactic, and transient sources. The remaining three telescopes are expected to be completed next year. In this presentation, I will report on the initial scientific results obtained with LST-1.
Speaker: Daniela Hadasch (ICE, CSIC) -
391
ASTRI-1: Early Data and Performance Highlights
The ASTRI Project is an international collaborative effort led by the Italian National Institute for Astrophysics (INAF) to develop, build, and operate a facility consisting of nine four-meter class Imaging Atmospheric Cherenkov Telescopes dedicated to gamma-ray astronomy in the 1–200 TeV range. The ASTRI Mini-Array is currently being installed in Tenerife at the Observatorio del Teide, and the first telescope, named ASTRI-1, is now fully operational.
The commissioning phase began in November 2024, and ASTRI-1 has been collecting data regularly from the Crab Nebula, the standard candle of very high-energy gamma-ray astronomy. The data sample consists of approximately 85 hours of observations at low zenith angles and 55 hours at higher zenith angles, collected between November 2024 and early 2025, under varying night sky illumination conditions (dark and moonlight). The Crab Nebula was observed in wobble mode, with equal amounts of data divided into four symmetrical positions with offset angles ranging from 0.5° to 4.5°.
In this contribution we present the telescope’s performance evaluated in the current status of the commissioning phase. We also report on the first scientific highlights achieved, with a focus on the analysis of the Crab Nebula, which provides key insights into the telescope sensitivity and performance. These preliminary results provide a strong foundation for future studies and pave the way for the next steps in the development of the ASTRI Mini-Array.Speaker: Silvia Crestan (INAF-IASF Milano) -
392
Performance and Characteristics of the First LACT Telescope
The Large Array of imaging Atmospheric Cherenkov Telescopes (LACT) consists of 32 telescopes, each with a 6-meter aperture, arranged within the array of the Large High Altitude Air Shower Observatory (LHAASO). LACT will leverage its high angular resolution in combination with LHAASO’s world-leading capability in gamma-proton discrimination to conduct detailed structural observations of very-high-energy gamma-ray sources. This will enable in-depth studies of particle acceleration processes and radiation mechanisms under extreme astrophysical conditions such as ultra-strong magnetic fields, super-dense matter states, and ultra-intense gravitational environments. The project aims to achieve internationally leading, breakthrough progress in understanding the origins and acceleration mechanisms of very-high-energy cosmic rays.
Following preliminary research and development, we have completed the design and prototype verification of the telescope mounting turntable. Significant progress has been made in the development of novel spherical mirrors, with some performance indicators reaching or even surpassing those of similar international products. We have also achieved domestic production of large-aperture ultraviolet bandpass filters and light concentrators.
Currently, the prototype of the LACT telescope mounting turntable has been successfully constructed at the LHAASO site, with all technical parameters meeting the expected targets. The Davies-Cotton mirror system has been installed and preliminarily commissioned, achieving the desired optical performance. The pointing calibration system has also been installed and tested.
Looking ahead, the plan is to complete the construction of eight telescopes by 2026, with concurrent scientific operations beginning during the construction phase. The full array of 32 telescopes is scheduled to be completed by 2028. Upon completion, LACT will become the most sensitive and highest angular-resolution array of Cherenkov telescopes in the world.Speaker: 玉东 王 (中国科学院高能物理研究所) -
393
Gamma-Ray and AntiMatter survey(GRAMS) experiment
The Gamma-Ray and AntiMatter Survey (GRAMS) is a next-generation experiment using a Liquid Argon Time Projection Chamber (LArTPC) detector to detect gamma rays and antiparticles. Gamma-ray surveys are important for understanding multi-messenger and time-domain astronomy, enabling exploration of the universe's most potent events, such as supernovae and neutron star mergers etc. Despite the significance of MeV gamma-rays, GRAMS could also explore the so-called 'MeV gap' region to improve MeV gamma-ray measurement sensitivity that was restricted by the hardness of accurately reconstructing Compton events. Aside from gamma-ray detection, the GRAMS proposed method also serves as an antiparticle spectrometer, targeting low-energy range cosmic-ray measurement. This talk will provide updates on the current status and progress towards the first prototype balloon flight with a small-scale LArTPC (pGRAMS) scheduled for early 2026, as well as the recent progress on antihelium-3 sensitivity calculation.
Speaker: Jiancheng Zeng (Northeastern University) -
394
The Southern Wide-field Gamma-ray Observatory
The Southern Wide-field Gamma-ray Observatory (SWGO) is a next-generation ground-based gamma-ray observatory under development in the Southern Hemisphere . Planned for installation at 4.8 km above sea level in the Atacama Astronomical Park in Chile, SWGO consists of an array of water Cherenkov detectors to measure gamma-ray emission over a wide energy range from hundreds of GeV to several PeV. By complementing CTA and existing Northern Hemisphere facilities, such as HAWC and LHAASO, SWGO will constrain the extreme physics of the multi-messenger universe, including but not limited to cosmic particle accelerators, transient phenomena, and fundamental physics. This presentation will highlight the status of the project, milestones of the developments, and key sciences that SWGO will deliver.
Speaker: Hao Zhou (Tsung-Dao Lee Institute, Shanghai Jiao Tong University) -
395
Prototype Test of a Water Cherenkov Detector Designed Based on the SWGO Lake Concept
This study presents the design and evaluation of a water Cherenkov detector (WCD) prototype based on the lake concept proposed in the SWGO framework. Aimed at future large-scale cosmic ray and gamma-ray observatories, the prototype uses a separate, stand-alone bladder structure made from lightweight materials. By using the natural buoyancy of water, the system removes the need for traditional mechanical support, providing a scalable and cost-effective solution for wide-field detector arrays. Its modular design allows for easy transportation and fast deployment, greatly reducing the need for complex infrastructure and lowering construction costs, especially in remote or challenging locations.
The prototype was first tested in a laboratory using cosmic-ray muons to systematically study its light response uniformity, time resolution, and detection efficiency. Field tests were then carried out by deploying a small detector array, consisting of water bladder units and LHAASO electromagnetic particle detectors (ED), on the artificial lake at the LHAASO site. The time response of the WCD was analyzed by calculating residuals with respect to the reconstructed shower front and comparing them with results from nearby ED detectors. Using coincidence-triggered data, the time synchronization performance of the WCD was thoroughly evaluated, demonstrating its potential for use in large-scale observatories.
With advantages in detecting low-energy electromagnetic particles and improving the timing accuracy of shower front measurements, the bladder-based WCD is well suited for next-generation experiments in the TeV–PeV energy range. Its strong scalability and ability to adapt to different environments make it a promising option for future observatories like SWGO and for possible upgrades to the LHAASO array, contributing to the development of low-cost, high-precision ground-based particle detection systems.
Speaker: 子奇 黄 (Shandong University)
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390
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Neutrino Physics and Astrophysics: parallel session 8A North Hall #1
North Hall #1
Convener: Piera Sapienza-
396
The Status and Perspectives of GRAND
The Giant Radio Array for Neutrino Detection (GRAND) is a large-scale project designed to detect ultra-high-energy (UHE) neutrinos at EeV energies using arrays of self-triggered radio antennas. By capturing radio emissions of air showers initiated by tau decays from neutrinos, GRAND aims to achieve unprecedented sensitivity and sub-degree angular resolution to those UHE neutrinos, marking a significant step towards the multi-messenger astronomy. Since October 2024, approximately 50 antennas for the GRANDProto300 have been operational in the Gobi Desert in Gansu Province, validating the instrumentation and design. This talk will present the scientific goals of GRAND, and outline the current status and future plans for this pioneering experiment.
Speaker: Guoyuan Huang (China University of Geosciences (Wuhan)) -
397
Recent results from Baikal-GVD
Baikal-GVD is a large underwater neutrino detector currently under construction in Lake Baikal, Russia. With an instrumented volume already approaching 0.6 km$^3$ and a sub-degree angular resolution, Baikal-GVD is starting to provide meaningful constraints on high energy neutrino sources. We review the current status of Baikal-GVD and recent results obtained with the partially completed instrument. This includes a measurement of the astrophysical diffuse neutrino flux, an analysis probing the Galactic diffuse neutrino flux, and searches for localized neutrino sources.
Speaker: Dmitry Zaborov (INR, Moscow, Russia) -
398
TRIDENT: Advancing Future Deep-sea Neutrino Observatory
The TRopIcal DEep-sea Neutrino Telescope (TRIDENT), a next-generation neutrino observatory initiated by Shanghai Jiao Tong University, will be deployed in the western Pacific Ocean to investigate high-energy astrophysical neutrino sources. TRIDENT will significantly enhance cosmic neutrino measurements across all flavors, offering unprecedented sensitivity for diverse physics studies. This talk will present TRIDENT's development, including: (1) its inception, (2) 2024 sea trial results, (3) ongoing Phase-I implementation with 10 detector strings, and (4) the planned in-situ calibration strategies. We will highlight the scientific potential for future multi-cubic-kilometer telescope arrays, particularly for dark matter detection.
Speaker: Xin Xiang (Shanghai Jiao Tong University) -
399
Sensitivity for ultra-high-energy neutrinos with the Radio Neutrino Observatory in Greenland (RNO-G)
The Radio Neutrino Observatory Greenland (RNO-G) is searching for Askaryan radio signals from ultra-high-energy neutrinos ($E \ge 100\,$PeV) interacting in ice. RNO-G utilizes a hybrid station design, which features radio antennas installed in 100$\,$m deep boreholes as well as in hand-digged trenches near the surface. At present, 8 hybrid stations are already operational and collecting science data near the apex of the Greenland ice sheet. The completed observatory will consist of 35 autonomously operating stations deployed over an area of about 50$\,$km$^2$. Its projected sensitivity will allow to test several models of astrophysical and cosmogenic neutrinos with the potential to detect neutrinos above 100$\,$PeV.
In this contribution, I will give an overview over the in-ice radio detection of ultra-high-energy neutrinos with RNO-G and present recent estimates of the RNO-G sensitivity.
Speaker: Jethro Stoffels (IIHE-VUB) -
400
High-energy neutrinos from low-luminosity gamma-ray bursts
The origin of high-energy neutrinos is still unknown, while gamma-ray bursts, the most powerful and luminous transients in the universe, remain a viable candidate. Even though IceCube observations stringently constrain the contribution from the typical long GRBs, the low-luminosity GRBS (LL GRBS) are promising candidates to be the main population of the diffuse neutrinos. In this work, we perform a comprehensive study of LL GRBs, particularly those that occurred during the IceCube experiment. We discuss the theoretical interpretation of LL GRBs, where we utilized the X-ray, gamma-ray, and neutrino observational data of the four LL GRBs to constrain the physical parameters of the LL GRB model. Our results have implications for the LL GRB contribution to diffuse neutrinos. In the future, more LL GRBs will be discovered. The real-time search of the coincidences between LL GRBs and high-energy neutrinos would provide direct evidence of LL GRBs21 as sources of neutrinos.
Speaker: Bing Theodore Zhang -
401
Status and Prospects of the TRIDENT Neutrino Telescope
Building on landmark detections of high-energy astrophysical neutrinos over the last decade, next-generation neutrino telescopes are poised to unlock insights into the most energetic phenomena in the Universe. TRIDENT is a developing neutrino observatory designed to significantly extend the reach and capabilities of current high-energy neutrino experiments. Located 3.5 km deep in the South China Sea, TRIDENT will instrument approximately 10 km³ of seawater with kilometer-long strings of advanced photosensitive modules. The primary goals of the experiment are to rapidly discover multiple astrophysical neutrino sources, and strongly boost the measurement precision of their neutrino flavor composition. This talk presents the current status and recent progress of TRIDENT, including the imminent deployment of Phase-1, featuring the first 10 detector strings. Prospects of the experiment are also discussed point-source discovery potential, flavor discrimination capabilities, and sensitivity to supernova burst neutrino signals.
Speaker: Iwan Morton-Blake (Tsung-Dao Lee Institute / Shanghai Jiao Tong University)
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396
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Neutrino Physics and Astrophysics: parallel session 8B North Hall #2
North Hall #2
Convener: Ke Han (上海交通大学)-
402
Impact of coherent scattering on relic neutrinos boosted by cosmic rays
Ultra-high-energy cosmic rays (UHECR) scattering off the cosmic relic neutrino background have recently gained renewed interest in the literature. Current data suggest that UHECR are predominantly made of heavy nuclei. Since the energy of relic neutrinos can reach ∼O(10) MeV in the rest frame of the UHECR, the cross section of heavy nuclei scattering off relic neutrinos can be coherently enhanced, which is similar to the coherent elastic neutrino-nucleus scattering (CEνNS) observed at low-energy neutrino experiments. We calculate the diffuse flux of relic neutrinos boosted by UHECR by taking into account the contributions from both the coherent and incoherent scatterings. Using current data from the IceCube Neutrino Observatory and the Pierre Auger Observatory, we place constraints on the overdensity of relic neutrinos down to $10^7$. Since the flux of boosted relic neutrinos peaks at an energy of ∼O(100)PeV, we also entertain the possibility to explain the recently observed KM3NeT event with boosted relic neutrinos from UHECR.
Speaker: Jiajun Liao (Sun Yat-sen University) -
403
Searching for sterile neutrinos at the keV scale with the KATRIN experiment
The KATRIN experiment is designed to measure the neutrino mass $m_{β}$ by analysing the endpoint region of the tritium β spectrum. KATRIN has set the world best limit of $m_{β}$ < 0.45 eV (90% C.L.) from the combined analysis of the first five measurement campaigns.
Using the same data sets, KATRIN has recently published new results in the search for sterile neutrinos at the eV scale, complementing reactor and radioactive source experiments.
With an endpoint of 18.6 keV, tritium also offers high potential for extending KATRIN’s physics programme, mainly by searching for sterile neutrinos at the keV scale. Such a project requires the measurement of the entire β spectrum. However, the current KATRIN detector is not designed to handle the higher count rate that occurs over such a wide energy range.
Equipped with a new, faster detector called TRISTAN, KATRIN aims to search for keV sterile neutrinos across the entire tritium β spectrum with a sensitivity on the active-sterile mixing down to $10^{-6}$. TRISTAN, a multi-pixel device based on Silicon Drift Detector technology, is currently in production and will be installed in the KATRIN beamline in 2026.
In this talk, I will present the latest results on the development of the TRISTAN detector, as well as the challenges involved in developing a model of the full tritium β spectrum in order to perform a high-sensitivity keV sterile neutrino search with KATRIN.Speaker: Andrea Nava (University of Milano-Bicocca) -
404
Probing new light particles in tritium beta decay with the KATRIN experiment
The Karlsruhe Tritium Neutrino (KATRIN) experiment is designed to measure the effective electron antineutrino mass with a sensitivity better than $m_\nu c^2=0.3\,\text{eV}$ (90% C.L.) in a kinematic approach by applying precision electron spectroscopy to the beta decay of molecular tritium. The measurement focuses on the spectral endpoint ($E_0$) region, extending up to tens of $\text{eV}$ below $E_0 \approx 18.6\,\text{keV}$.
Light neutral pseudoscalar or vector bosons arise in various theories beyond the Standard Model. Constraints on their couplings to neutrinos or electrons can be derived from cosmological, astrophysical and laboratory observations. KATRIN complements these approaches, as the emission of an additional light state in tritium decay introduces characteristic modifications to the observed electron energy spectrum. We present the sensitivity of KATRIN to such new light bosons, based on data from 2019, corresponding to $4 \times 10^6$ electrons in the analysis interval of $[-40, +130]\,\text{eV}$ around $E_0$.
This work is supported by the Helmholtz Association and by the Ministry for Education and Research BMBF (grant numbers 05A23PMA, 05A23PX2, 05A23VK2, and 05A23WO6) and the bwForCluster NEMO.
Speaker: Joscha Lauer (KIT) -
405
Latest Constraints on Sterile Neutrinos from the KATRIN Experiment
The Karlsruhe Tritium Neutrino (KATRIN) experiment performs a measurement of the effective electron neutrino mass with sub-eV sensitivity through high-precision spectroscopy of the tritium $\beta$-decay spectrum. Analysing 36 million $\beta$-electrons from five measurement campaigns, KATRIN presently provides an upper limit on the neutrino mass of $m_\nu < 0.45~\text{eV}$ at 90\% confidence.
In addition to its primary goal, KATRIN probes the existence of eV-scale sterile neutrinos by searching for distortions in the $\beta$-spectrum due to active-sterile neutrino mixing. New constraints in a minimal 3+1 sterile neutrino framework exclude significant regions of parameter space, particularly those motivated by short-baseline neutrino oscillation anomalies. These results complement reactor-based oscillation experiments such as STEREO and PROSPECT, disfavoring regions of parameter space previously supported by global oscillation fits and excluding the parameter space favored by the Neutrino-4 experiment. This talk will present the latest results from the KATRIN experiment based on a 259-day data set.Speaker: Shailaja Mohanty (Karlsruhe Institute of Technology) -
406
Search for keV-Scale Sterile Neutrinos via $^3$H Beta Decay in LiF Crystals
Understanding the nature of dark matter is one of the fundamental challenges in modern physics. Numerous experimental and theoretical attempts have explored the possibility that keV-scale sterile neutrinos could serve as a strong dark matter candidate. Although satellite observations have placed stringent limits on the mixing of sterile neutrinos with active Standard Model neutrinos, these constraints can vary depending on early-universe models. A precise measurement of a beta decay spectrum offers a model-independent approach to investigating the mixing angle between active and sterile neutrinos.
We have conducted the LiF Experiment for keV Sterile Neutrino Search (LiFE-SNS) by measuring the tritium beta decay energy spectrum using LiF crystals read out by magnetic microcalorimeters (MMCs) at millikelvin temperatures. Over a four-month data-taking period, two LiF detectors, each containing approximately 30 Bq of tritium embedded through neutron activation, were operated with an energy threshold of approximately 1 keV.
We present the analysis procedures used to extract a precise beta spectrum from the measured signals, based on Monte Carlo simulations that incorporate both the theoretical beta spectrum and experimental noise data. We will present search results for sterile neutrinos in the 1–17 keV mass range, covering mixing amplitudes between 10$^-4$ and 10$^-2$.Speaker: Dr KyungRae Woo (Institute for Basic Science) -
407
Searches for New Physics in the DANSS Experiment
DANSS is a scintillator detector of antineutrinos located on a lifting platform below the 4th reactor core of Kalininskaya NPP in Russia. The detector position below the reactor core provides advantages of high neutrino rate and moderate overburden of 50 m w.e., which suppresses atmospheric muon flux by a factor of 5–6. The detector was commissioned in April 2016 and it has been operating continuously since October 2016. The antineutrino statistics exceeds 10M IBD events. This talk presents searches for sterile neutrinos and large extra dimensions (LED) using ratios of antineutrino spectra at various distances from the reactor core. This ratio-based approach avoids dependence on reactor spectra models and detector efficiency uncertainties. No statistically significant evidence of either effect was found. The limits in the sterile neutrino parameter space were set using Gaussian CLs method. The DANSS result effectively excludes the region preferred by the recent BEST data below $\Delta m^2 = 5$ eV$^2$. The exclusion region in the LED parameter space generally agrees with Daya Bay result, but is more strict in some regions and is obtained in a model-independent way. We also present results on the high energy tail (above 10 MeV) of reactor antineutrinos. The talk will cover the DANSS upgrade status as well.
Speaker: Igor Alekseev (NRC "Kurchatov Institute") -
408
Testing the Gallium neutrino anomaly with CEvNS?
The capability to perform precision measurements of nuclear form factors or coupling constants with CEvNS relies on precise knowledge of the incoming neutrino flux and energy spectrum. Isotopes decaying via electron capture (EC) represent a close-to-ideal neutrino source, thanks to the monoenergetic spectrum and the possibility of precisely measuring the source activity. However, the low energy of emitted neutrinos would require detectors with a trigger threshold at the eV level.
Lithium is the only target material that could practically be used to detect EC neutrinos, at the cost of a poor event rate due to the low neutron content. First, lithium’s low nuclear mass would relax the threshold requirement up to 50 eV. Second, several lithium-containing crystals are commercially available and could be used as bolometers. Third, lithium can easily be enriched to 99% in 6Li or 7Li, allowing to perform a differential measurement of the neutrino flux and to disentangle the vector and axial-vector components of CEvNS.
A serendipitous byproduct of a bolometric CEvNS measurement with an EC source is the possibility to perform a truly independent test of the Gallium neutrino anomaly through a new detection channel. Such a measurement could allow us to pinpoint the origin of this long-standing puzzle, discriminating between a miscalculation of the source activity and any possible gallium-related effects.
In this contribution, we will present the requirements for a future lithium-based bolometric experiment and its sensitivity for a cross-check of the Gallium neutrino anomaly via the CEvNS detection.Speaker: Giovanni Benato (Gran Sasso Science Institute)
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402
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Underground Laboratories: parallel session 8 North Hall #3
North Hall #3
Convener: Hide-Kazu TANAKA (Kamioka Obs., ICRR, University of Tokyo)-
409
Omnidirectional Photon Time Projection with Large Liquid Neutrino Detectors
The liquid scintillation and Cherenkov detectors are the selected detection technologies for next-generation neutrino detectors at 10-100kt scale. Traditionally, they function primarily as calorimeters. Time-of-flight methods have long been employed to reconstruct event vertices. With the advancement of fast photon-sensors and electronics readout, as well as mathematical and computational imaging theories, it has become feasible to extract particle interaction tracks from data analysis, akin to time projection chambers with omnidirectional photons in place of drifted electrons.
In this talk, I am going to review the efforts on a unified fully probabilistic scintillation-Cherenkov reconstruction framework to open up new paradigms for tracking in non-segmented large liquid detectors.
Speaker: Benda Xu (Tsinghua University) -
410
Design Plan and Development Progress of the LACT SiPM Camera
The LACT project will deploy 32 six-meter aperture Cherenkov telescopes on Haizi Mountain in Daocheng, Sichuan, to conduct fine-structure measurements of multiple ultra-high-energy gamma-ray sources discovered by LHAASO. The SiPM camera is located at the focal plane of the telescope, 8000 mm from the center of the mirror dish. The SiPM camera measures atmospheric Cherenkov light, which is focused onto its surface by the mirror using an imaging technique. The camera consists of 1616 SiPM units arranged in a regular octagonal structure. This report will present the design plan and development progress of the LACT SiPM camera.
Speaker: Mingjie Yang (Institute of High Energy Physics, Chinese Academy of Sciences) -
411
Progress on the NνDEx high pressure vessel and gas system
The neutrinoless double beta decay (0νββ) experiment aims to investigate whether neutrinos are Majorana fermions (i.e., whether they are their own antiparticles). NνDEx is to use a time projection chamber (TPC) for trajectory detection, and readout with the low-noise CMOS chips to measure the neutrinoless double beta decay in the China Jinping underground laboratory. High-pressure (1.0 MPa) SeF6 will serve as the working medium for TPC. The concept design of NνDEx consists of readout chips, TPC, copper shielding structures, a stainless-steel high pressure gas vessel, a gas circulation system, and external shielding assemblies.
The high pressure vessel as well as the inner copper shielding structures and the corresponding gas circulation system have been designed. Up to now, the high pressure vessel has been assembled and placed in a ground laboratory in Lanzhou for principle study. The gasproofness of the high pressure vessel has been investigated with different methods. Currently, the gas circulation system is being assembled. More details of the high pressure vessel and gas circulation system will be shown in the presentation.
Speaker: Qiang Hu (Institute of Modern Physics, Chinese Academy of Sciences) -
412
Characterization of the JUNO Liquid Scintillator with Proton and Carbon Beams
Baryon number violation, predicted by many GUT frameworks, motivates current searches for proton decay. The decay channel $\text{p} \rightarrow \text{K}^{+} + \bar{\nu}$, favored in many SUSY-GUT models, currently has a partial lifetime limit of $5.9 \times 10^{33}$ yr at 90 % C.L. set by the Super-Kamiokande collaboration. JUNO, a 20 kton liquid scintillator detector under commissioning in China, is expected to reach a sensitivity of $9.6 \times 10^{33}$ yr at 90 % C.L. with 200 kton$\times$yr exposure.
Efficient signal-background discrimination for this channel in JUNO relies on resolving the time-correlated double-peak signature from the kaon and its decay chain, in contrast to predominantly single-peak signatures from atmospheric neutrino backgrounds. The relative amplitude of the primary kaon peak is governed by quenching effects, modeled via Birks’ law and its Chou extension.
To characterize the scintillator response, the UniKaon setup was deployed at the Heidelberg Ion Therapy Center for proton beams with $\mathcal{O}(100 \text{ MeV})$ energies. Additionally, quenching of carbon ion beams was measured for the first time in a liquid scintillator context. This contribution presents the extracted Birks' parameters for protons and carbon ions in JUNO LS. Using constraints from atmospheric muon data from UniKaon, the kaon light emission behavior is extrapolated and implications for signal efficiency in $\text{p} \rightarrow \text{K}^{+} + \bar{\nu}$ searches are discussed. Beyond proton decay, these results inform the modeling of visible energy from atmospheric and supernova neutrino interactions.
Speaker: Ulrike Fahrendholz (Technical University of Munich) -
413
Magnetic dipole-dipole transition for scintillation quenching
A magnetic dipole-dipole interaction is proposed as a scintillation quenching mechanism. The interaction rate follows $R^{-6}$ as the electric dipole-dipole interaction in Foster resonance energy transfer theory. The proposed mechanism causes a long-range resonance energy transfer, and the resonance condition is that the spins of donor and acceptor electrons both flip, and the energy level differences are the same. When oxygen or organic molecules including heavy elements are dissolved in a liquid scintillator, these requirements are easier to satisfy. The proposal in the paper adds a new approach for scintillation quenching in liquid scintillators.
Speaker: Zhe Wang (Tsinghua University) -
414
Current status and technical aspects of GRANDProto300
GRANDProto300 is a prototype of GRAND (Giant Radio Array for Neutrino Detection) in Xiaodushan (40.99$^{\circ}$N, 93.94$^{\circ}$E) in Dunhuang, China. The detector will feature 300 radio antennas to cover a total geometrical area of $\sim$200 km$^{2}$. The experiment aims to demonstrate the autonomous detection of radio emissions from air showers produced by high-energy astroparticles. The first 65 antennas, installed by April 2025, are now stably taking the data. Data analysis is actively ongoing to calibrate the antennas, test trigger conditions for adio autonomous detection, search for cosmic-ray event candidates, and more. Simulation-based studies are also performed to estimate the exposure to cosmic-ray events and reconstruct their physical parameters such as energy and direction. This talk will first introduce the concept and the current status of the experiment and present the technical aspects including instrumentation, simulation studies, and the results of data analysis.
Speaker: Sei Kato (Institut d'Astrophysique de Paris)
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409
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Plenary session Lufeng Hall
Lufeng Hall
Convener: Aldo Ianni (INFN LNGS)-
415
Review of underground laboratories worldwide
The world’s deep underground laboratories are special places for science. The current facilities are hosting a wide range of exciting, international, fundamental science studies and enabling the development of new technologies and techniques of importance and impact far beyond pure low background particle physics. The range of science undertaken in these laboratories is also growing, now including studies in the areas such as Earth and environmental sciences, biology, planetary exploration technology development and beyond. This talk will give an overview of the World’s current deep underground science facilities, the science being undertaken in them now and plans for change and growth at the facilities in the future.
Speaker: Sean Paling -
416
Searching for the origin of Cosmic Rays
In this talk, I will review recent progress in the measurement of Galactic and extragalactic cosmic rays, along with advances in their theoretical interpretation.For Galactic cosmic rays, in addition to direct observations from space-based experiments such as AMS-02, CALET, and DAMPE, the proton spectrum or the first time has been measured in the knee region by the ground-based LHAASO experiment. Detailed measurements of the diffuse gamma-ray background from the Galaxy have also been performed—below 1 TeV by Fermi, and from 1 TeV to 1 PeV by HAWC and LHAASO. Furthermore, the diffuse neutrino flux from the Galaxy has been measured for the first time by IceCube, with independent indications of an excess also reported by ANTARES and Baikal-GVD. I will present models of cosmic ray sources that are consistent with these multi-messenger observations and discuss how future measurements could help distinguish between them.
For extragalactic cosmic rays, I will review the main observational results from the Pierre Auger Observatory and the Telescope Array experiments. I will highlight recent advances in the combined interpretation of anisotropy, energy spectrum, and mass composition data and their connection to progress in understanding of Galactic and inter-galactic magnetic fields. Finally, I will discuss current prospects for probing the transition region between Galactic and extragalactic cosmic rays.Speaker: Dmitri SEMIKOZ (APC, Paris) -
417
Probing Fundamental Physics of the Universe with Stellar Explosions
Supernovae come into two main subclasses, with one from core collapse expsloion of massive stars and the other one from thermonuclear explosion of white dwarfs in binary system. The former, dubbed as core-collapse supernovae (CCSNe), carries fundamental physics involved in evolution and explosions of massive stars such as neutrino, gravitational wave, and shock breakout. Whereas the latter, dubbed as thermonuclear supernoave (SNe Ia), allows constraints on cosmic expansion rate and nature of dark energy. In this talk, I will review the progress in our understanding of both CCSNe and SNe Ia and their implications for some fundamental physics. In particular, recent successful detections of extremely early emission immediately after the explosion of some CCSNe provide direct evidence for the mechanism of jet-driven, aspherical explosion. Moreover, the tension found in the measurement of cosmic expansion rate (i.e., Hubble constant) from SNe Ia relative to the result from early universe probes requires a comprehesive understanding of SN Ia physics, which will be highlighted in the talk as well.
Speaker: Xiaofeng Wang (Tsinghua University)
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415
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Coffee break International Conference Center
International Conference Center
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Plenary session Lufeng Hall
Lufeng Hall
Convener: Bingsong Zou-
418
Detection of supernovae, solar and geo-neutrinos – review
This talk will review progress on the detection of supernovae, solar and geo neutrinos. This is an area of significant interest and scientific activity, with major players currently including Borexino, KamLAND, SNO+ and SuperKamiokande, and with a number of major new facilities of relevance coming online in the near future, including JUNO, DUNE and HyperK. Owing to time constraints, the focus here will be on recent observations and implications from (pre)existing experiments, as well as the current state of readiness for supernova neutrino detection. Prospects for future observations will also be noted.
Speaker: Prof. Steven Biller (Oxford University) -
419
Interpreting Earth's geoneutrino flux
The surface heat flux of the Earth is 46 $\pm$ 3 TW (terawatts, 10$^{12}$ watts) or on average about 90 mW/m$^2$ and is the sum of contributions from primordial and radiogenic sources. Often geologists predict Earth's radiogenic power at 20 $\pm$ 10 TW, which comes from heat-producing elements (K, Th \& U). However, the full range of published estimates spans from 10 to 30 TW, documenting a factor of 3 variation in Earth's predicted heat production. The continental crust is uniformly estimated to have 7.1$^{+2.1}_{-1.6}$ TW radiogenic power. Consequently, the convecting mantle is estimated to have the remaining radiogenic power at between 1 and 26 TW, which is more than an order of magnitude of uncertainty. The contribution of radiogenic heat from K decay is 20\% of the total signal and K geoneutrinos cannot be detected with current technologies. Time-integrated $^{208}$Pb/$^{206}$Pb isotope data for 10$^3$ rocks document the Earth's Th/U molar ratio being identical to that of the solar system, that is 3.90.
Recent particle physics findings challenge this dominant geological paradigm with experimental results reporting the measured geoneutrino flux from Th and U. Taking the experimentally measured flux in TNU (terrestrial neutrino units) and converting to Earth's power gives 15.4$^{+8.3}_{-7.9}$ TW for KamLAND (Japan), 31.3$^{+13.6}_{-12.7}$ TW for Borexino (Italy) and 63$^{+62}_{-56}$ TW for SNO+ (Canada) (Abe et al., 2022; Abreu et al., 2025; Agostini et al., 2020). Although uncertainties allow these model predictions to overlap with geological models, Borexino's predicted high central value for mantle power is due to an inaccurate estimate of near-field (local) geoneutrino flux (Sammon and McDonough, 2022), and that for SNO+ is simply well above Earth's measured heat flux.
We welcome this opportunity to highlight the fundamentally important resource offered by the physics community and call attention to the shortcomings associated with the characterization of the geology of the Earth. We review the findings from continent-based physics experiments, the predictions from geology, and assess the degree of mismatch between the physics measurements and predicted models of the continental lithosphere, the conductive lid, which is the product of continent formation and is not involved in mantle convection.
The large uncertainties associated with the recently reported geoneutrino flux measurement at SNO+ limit its usefulness. We anticipate that a year of JUNO data will provide a significant advance towards constraining the mantle geoneutrino flux. Data from the developing Jinping experiment, located in an extra-thick crust ($\sim$55 km thick vs. normally 36 km), will provide additional insights when used with the data from nearby experiments of JUNO and KamLAND, with the latter being approximately one mantle depth east of the Jinping experiment.
Detection of a geoneutrino signal in the ocean, far from the influence of continents, offers the potential to resolve this tension. Neutrino geoscience is a powerful new tool for interrogating the composition of the continental crust and mantle and its structures.
S Abe, S Asami, M Eizuka, et al. Abundances of uranium and thorium elements in Earth estimated by geoneutrino spectroscopy. Geophysical Research Letters, 49(16):e2022GL099566, 2022.DOI: 10.1029/2022GL099566.
M Abreu, V Albanese, A Allega, et al. Measurement of reactor antineutrino oscillation at SNO+. arXiv preprint arXiv:2505.04469, 2025.
M Agostini, K Altenm¨uller, S Appel, et al. Comprehensive geoneutrino analysis with Borexino. Physical Review D, 101(1):012009, 2020. DOI: 10.1103/PhysRevD.101.012009.
LG Sammon and WF McDonough. Quantifying Earth’s radiogenic heat budget.
Earth and Planetary Science Letters, 593:117684, 2022. DOI: 10.1016/j.epsl.2022.117684.Speaker: William McDonough (Tohoku University) -
420
The DUNE Experiment: Status and Physics Prospects
The Deep Underground Neutrino Experiment (DUNE) is a next-generation long-baseline neutrino experiment that will address key open questions in neutrino physics. A powerful >2 MW wide-band beam from Fermilab will be directed to a 40-kiloton liquid argon time projection chamber (LArTPC) far detector 1,300 km away in South Dakota, enabling an unambiguous determination of the neutrino mass ordering and a precise search for CP violation. DUNE will be deployed in two phases: in the first phase, two LArTPC modules will be installed—one using horizontal-drift and one vertical-drift technology—both validated through full-scale prototypes at CERN. The near detector complex will precisely characterize the unoscillated neutrino flux and constrain systematic uncertainties. This contribution will present the experiment’s current status and its physics prospects. DUNE also offers unique sensitivity to supernova and solar neutrinos. Installation begins soon, with physics data taking expected in 2030.
Speaker: Luis Manzanillas (LAPP - IN2P3 - CNRS / Université Savoie Mont Blanc) -
421
Status of the Hyper-Kamiokande experiment
The excavation of the large underground cavern for the Hyper-Kamiokande experiment is now nearing completion. In this talk, I will present the current status and the progress of the Hyper-Kamiokande detector construction, and the prospects for the upcoming phases of the project.
Speaker: Hide-Kazu TANAKA (Kamioka Obs., ICRR, University of Tokyo) -
422
First performance results from the JUNO experiment commissioning phase
The Jiangmen Underground Neutrino Observatory (JUNO) is the largest liquid scintillator detector for neutrino physics ever built. At the end of 2024 the construction of the detector has ended and both Central Detector and the surrounding Water Cherenkov Detector have been filled with ultra pure water. At the beginning of February 2025, after having filled the complete detector, a short commissioning run has been taken and few days afterwards water in the Central Detector has been started to be replaced with Liquid Scintillator. During this longer filling phase, the detector has been switched on and regular calibration and commissioning runs have been collected to understand the response of the detector and study its performances. In the present talk preliminary results on JUNO performances during filling will be shown.
Speaker: Alberto Garfagnini (Padova University and INFN-Padova)
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418
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Closing session Lufeng Hall
Lufeng Hall
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423
Best Poster Award ceremony and Closing remarksSpeaker: Qian Yue (Tsinghua University)
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423
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Lunch Yu’ou Building
Yu’ou Building
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Visit CJPL CJPL
CJPL
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