Multicomponent dark matter in extended U(1)B−L: neutrino mass and high scale validity

Abstract

Standard Model with right handed neutrinos charged under additional U(1)B−L gauge symmetry offer solutions to both dark matter (DM) problem and neutrino mass generation, although constrained severely from relic density, direct search and Higgs vacuum stability. We therefore investigate a multicomponent DM scenario augmented by an extra inert scalar doublet, that is neutral under U(1)B−L, which aids to enlarge parameter space allowed by DM constraints and Higgs vacuum stability. The lightest right-handed neutrino and the CP-even inert scalar are taken as the dark matter candidates and constitute a two component dark matter framework as they are rendered stable by an unbroken ℤ2 × ℤ2′ symmetry. DM-DM conversion processes turn out crucial to render requisite relic abundance in mass regions of the RH neutrino that do not appear in the stand-alone U(1)B−L scenario. In addition, the one-loop renormalisation group (RG) equations in this model demonstrate that the electroweak (EW) vacuum can be stabilised till ∼ 109 GeV in a parameter region compatible with the observed relic, the direct detection bound and other relevant constraints. We finally comment on the possibility of including the freeze-in mechanism in the same set-up.