capable of accommodating one of the three right handed neutrinos as a freeze-in type of
dark matter where the required smallness of the associated coupling is connected to the
lightness of the (smallest) active neutrino mass. It turns out that (a) the nonthermal
production of dark matter having mass≲ O (1) MeV (via decays of W, Z bosons and standard
model Higgs) consistent with relic density and (b) its stability determine this smallest active …