Majorana Dark Matter and Neutrino mass in a singlet-doublet extension of the Standard Model

Abstract

A minimal extension of the Standard Model (SM) by a vector-like fermion doublet and three right handed (RH) singlet neutrinos is proposed in order to explain dark matter and tiny neutrino mass simultaneously. The DM arises as a mixture of the neutral component of the fermion doublet and one of the RH neutrinos, both assumed to be odd under an imposed ${\mathcal{Z}}_2$ symmetry. Being Majorana in nature, the DM escapes from $Z$-mediated direct search constraints to mark a significant difference from singlet-doublet Dirac DM. The other two ${\mathcal{Z}}_2$ even heavy RH neutrinos give rise masses and mixing of light neutrinos via Type-I Seesaw mechanism. Relic density and direct search allowed parameter space for the model is investigated through detailed numerical scan.

DAE-BRNS-HEP symposium 2020 Proccedings