Baryogenesis via Leptogenesis from Asymmetric Dark Matter and radiatively generated Neutrino mass

TL;DR

This paper presents a model extending the Standard Model with a dark sector to explain baryogenesis via leptogenesis, generate neutrino masses radiatively, and account for dark matter, with experimental constraints considered.

Contribution

It introduces a novel dark sector extension that links dark matter asymmetry, neutrino mass generation, and baryogenesis within a unified framework.

Findings

Dark matter asymmetry generated by heavy neutrino decay

Neutrinos acquire sub-eV masses at one loop

Constraints from Higgs decay and direct detection analyzed

Abstract

We propose an extension of the standard model (SM) by including a dark sector comprising of three generations of heavy right-handed neutrinos, a singlet scalar and a singlet Dirac fermion, where the latter two particles are stable and are viable candidates of dark matter (DM). In the early Universe, the CP-violating out-of-equilibrium decay of heavy right-handed neutrinos to singlet Dirac fermion and scalar in the dark sector generates a net DM asymmetry. The latter is then transported to the visible sector via a dimension eight operator which conserves $B-L$ symmetry and is in thermal equilibrium above the sphaleron decoupling temperature. An additional light singlet scalar is introduced which mixes with the SM Higgs and pave a path for annihilating the symmetric components of the DM candidates. Then we discuss the constraints on singlet-doublet Higgs mixing from invisible Higgs decay, signal strength at LHC and direct search of DM at terrestrial laboratories. At tree level the neutrinos are shown to be massless since the symmetry of dark sector forbids the interaction of right-handed neutrinos with the SM particles. However, at one loop level the neutrinos acquire sub-eV masses as required by the oscillation experiments.