Conveners
Cosmology and Particle Physics: parallel session 1
- Huaike Guo (中国科学院大学（ICTP-AP）)
Cosmology and Particle Physics: parallel session 2
- Jun Zhang (University of Chinese Academy of Sciences)
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...
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...
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...
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...
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...
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.
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...
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...
