1210.6852 (Kyle Allison)

Dark matter, singlet extensions of the nuMSM, and symmetries    [PDF]

Kyle Allison

We consider an extension of the nuMSM in which sterile neutrino masses originate from the VEV of a Higgs singlet phi and dark matter is produced through the decays of phi rather than through active-sterile neutrino oscillations. This model, which we refer to as the nuNMSM, can readily satisfy constraints on warm dark matter from the Lyman-alpha forest. We show that the hierarchical parameters of the nuNMSM can arise from symmetries broken at or near the Planck scale for two specific models of the scalar sector: one in which phi stabilizes the electroweak vacuum and one in which phi is the inflaton. These models have several experimental signatures that are distinct from the nuMSM, including additional dark radiation that is relativistic at both primordial nucleosynthesis and CMB decoupling and, for the former, a large invisible branching ratio of the Higgs.

View original: http://arxiv.org/abs/1210.6852