Constraining keV sterile neutrino dark matter through lab and cosmo surveys

by Dr Manibrata Sen (Max-Planck-Institut für Kernphysik, Heidelberg)

Thursday 5 May 2022, 11:00 → 12:00 Europe/Berlin

Main/2-313 - 313 ("also" via Zoom: https://mppmu.zoom.us/j/99300254726) (Main)

keV-scale gauge-singlet fermions, allowed to mix with the active neutrinos, are elegant dark matter (DM) candidates. They are produced in the early universe via the Dodelson-Widrow mechanism and can be detected as they decay very slowly, emitting X-rays. In the absence of new physics, this hypothesis is virtually ruled out by astrophysical observations. In this talk, I will demonstrate that new interactions among the active neutrinos allow these sterile neutrinos to make up all the DM while safely evading current astrophysical bounds. I will discuss new bounds on such sterile neutrino DM models, arising from extra production of sterile neutrinos in core-collapse supernovae. Furthermore, neutrino interactions mediated by a sub-MeV scalar can also lead a lower bound on the amount of extra radiation in the early Universe. Such models can, therefore, receive strong constraints from next generation cosmology experiments, like CMB-S4. In general, the talk will try to focus on different ways one can constrain sterile neutrino dark matter from lab, as well as cosmological and astrophysical bounds.