Neutrino spectrum in SU$(3)_\ell\times$SU$(3)_E$ gauged lepton flavor model

TL;DR

This paper explores a gauged lepton flavor symmetry model to explain neutrino masses, introducing new fermions and applying experimental and theoretical constraints to determine the minimal neutrino mass spectrum.

Contribution

It presents a minimal SU(3)$_\ell$×SU(3)$_E$ gauged lepton flavor model with anomaly cancellation and neutrino mass predictions based on unitarity and experimental constraints.

Findings

Lower bound on lightest neutrino mass for normal hierarchy: 3.76×10⁻³ eV.

Lower bound on lightest neutrino mass for inverted hierarchy: 18.9×10⁻³ eV.

Model incorporates a see-saw mechanism with new fermions.

Abstract

Massive neutrino is an evidence of new physics beyond the Standard Model. One of the well motivated new physics scenarios is a model with gauged lepton flavor symmetry. We investigate neutrino properties in the minimal SU$(3)_\ell\times$SU$(3)_E$ gauged lepton flavor model. In this model, three new species of fermions are introduced to cancel gauge anomalies. These new fermions lead to a see-saw mechanism for neutrino mass generation. We impose the constraints from perturbative unitarity in 2-2 scattering processes, as well as current experimental constraints, to obtain viable neutrino spectrum. We determine the lower bound, with the SU(3)$_\ell$ gauge coupling set to 1, on the lightest neutrino mass of $3.76\times10^{-3}\,(18.9\times10^{-3})\,$ eV for the normal (inverted) hierarchy.