Freeze-In Dark Matter and Leptogenesis: a $\psi'$SM route

TL;DR

This paper explores a model extending the Standard Model with an $E_6$ symmetry, where a residual $U(1)_{ ext{ extmu}}$ gauge symmetry facilitates freeze-in dark matter production and leptogenesis for baryon asymmetry.

Contribution

It introduces a novel $E_6$-based framework linking dark matter and baryogenesis through residual gauge symmetry and scalar decay mechanisms.

Findings

Freeze-in production can account for dark matter relic abundance.

Dark matter masses range from MeV to hundreds of GeV.

Leptogenesis explains the observed baryon asymmetry.

Abstract

We investigate the possibility of \emph{freeze-in} dark matter production and baryogenesis via leptogenesis in a $\psi'$SM model, which is an $E_6$ extension of the Standard Model, featuring a residual $U(1)_{\psi'}$ gauge symmetry. This symmetry arises from a linear combination of $U(1)_\chi$ and $U(1)_{\psi}$, both of which are subgroups of the $E_6$. The spontaneous breaking of $U(1)_{\psi'}$ symmetry governs the dynamics of a singlet fermion, which serves as a freeze-in dark matter candidate. The dark matter mass arises from dimension-five operators, and a discrete symmetry ensures its stability. We show that freeze-in production from scalar decay can yield the correct relic abundance for dark matter masses between a few MeV to a few hundred GeV. Simultaneously, heavy right-handed neutrinos generate light neutrino masses via the type-I seesaw and produce the observed baryon asymmetry via leptogenesis.