Signatures of pseudo-Dirac dark matter at high-intensity neutrino experiments

摘要: We (re)consider the sensitivity of past (LSND) and future (${\mathrm{JSNS}}^{2}$) beam dump neutrino experiments to two models MeV-scale pseudo-Dirac dark matter. Both LSND ${\mathrm{JSNS}}^{2}$ are close (24--30 m) intense sources light neutral mesons which may decay matter via interactions involving a mediator or dipole operators. The can then scatter inside nearby detector. show that higher energy resulting $\ensuremath{\eta}$ production improve on reach for light-mediator with masses greater than ${m}_{\ensuremath{\pi}}/2$. Further, we find both existing measurements severely constrain viable parameter space recently proposed model could explain 3.5 keV excess reported in observations stacked galaxy clusters Galactic center.