Dirac Neutrino Mass Matrix and its Link to Freeze-in Dark Matter

TL;DR

This paper proposes a model linking small Dirac neutrino masses with a dark gauge symmetry, suggesting a fermion singlet as a freeze-in dark matter candidate from Higgs decay.

Contribution

It introduces a novel mechanism connecting Dirac neutrino masses to a dark gauge symmetry with a realistic mass matrix derived from $S_3$ symmetry.

Findings

A natural small Dirac neutrino mass matrix is constructed.

Identification of a fermion singlet as a freeze-in dark matter candidate.

Dark sector dynamics enable dark matter production via Higgs decay.

Abstract

Using a mechanism which allows naturally small Dirac neutrino masses and its linkage to a dark gauge $U(1)_D$ symmetry, a realistic Dirac neutrino mass matrix is derived from $S_3$. The dark sector naturally contains a fermion singlet having a small seesaw mass. It is thus a good candidate for freeze-in dark matter from the decay of the $U(1)_D$ Higgs boson.