Leptonic asymmetry of the sterile neutrino hadronic decays in the nuMSM

Abstract

We consider the leptonic asymmetry generation in the nuMSM via hadronic decays of sterile neutrinos at T<<T_{EW}, when the masses of two heavier sterile neutrinos are between pion mass and 2 GeV. The choice of upper mass bound is motivated by absence of direct experimental searches for singlet fermions with greater mass. We carried out computations at zero temperature and ignored the background effects. Combining constraints of sufficient value of the leptonic asymmetry for production of dark matter particles, condition for sterile neutrino to be out of thermal equilibrium and existing experimental data we conclude that it can be satisfied only for mass of heavier sterile neutrino in the range 1.4 GeV < M < 2 Gev and only for the case of normal hierarchy for active neutrino mass.