A $Z_4$ symmetric inverse seesaw model for neutrino masses and FIMP dark matter

TL;DR

This paper proposes a $Z_4$ symmetric inverse seesaw model that explains neutrino masses and FIMP dark matter production, linking neutrino phenomenology with dark matter relic abundance.

Contribution

It introduces a minimal $Z_4$ symmetric framework that simultaneously addresses neutrino masses and FIMP dark matter, extending the standard model with new fermions and scalars.

Findings

Successfully reproduces neutrino oscillation data.

Achieves correct dark matter relic density.

Connects neutrino properties with dark matter production.

Abstract

A theoretical framework based on a spontaneously broken $Z_4$ symmetry is proposed to simultaneously explain neutrino mass generation via the inverse seesaw mechanism and dark matter (DM) production through a freeze-in scenario. This work extends the standard model with right-handed neutrinos $N_i$, additional fermions $\chi_i$, and a complex scalar $S$. An unbroken $Z_2$ subgroup ensures the stability of the DM candidate, whose relic abundance is dominantly produced via decay and scattering processes involving heavy singlet fermions. Phenomenological analyses show that this relatively minimal construction accommodates the observed neutrino oscillation parameters, consistent with the latest global fit data. Furthermore, the model successfully reproduces the observed DM relic density within the parameter space relevant to neutrino phenomenology, establishing a connection between neutrino properties and DM production.