Thermal keV dark matter in a gauged B-L model with cosmic inflation

Understand

We investigate the possibility of keV scale thermal dark matter (DM) in a gauged $B - L$ extension of the standard model with three right-handed neutrinos (RHN) and one vector like fermion in the context of cosmic inflation.

• The complex singlet scalar field responsible for the spontaneous breaking of $B-L$ gauge symmetry is non-minimally coupled to gravity and serves the role of inflaton.
• The keV scale vector like fermion DM gives rise to the possibility of warm dark matter, but it gets overproduced thermally.
• The subsequent entropy dilution due to one of the RHN decay can bring the thermal abundance of DM within the observed limit.