keV scale $\nu_R$ dark matter and its detection in $\beta$ decay experiment

Understand

We study dark matter(DM) in the model with one keV scale right-handed neutrino $\nu_{R1}$ and two GeV scale right-handed neutrinos $\nu_{R2,3}$, the $\nu$SM.

• We find that one of the GeV scale right-handed neutrinos can have much longer lifetime than the other when two GeV scale right-handed neutrinos are degenerate.
• We show that mass and mixing of light neutrinos can be explained in this case.
• Significant entropy release can be generated in a reheating produced by the decay of one of the GeV scale $\nu_{R}$.