Speaker
Description
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.
| Collaboration you are representing | JNE |
|---|
