Neutrino masses in an $SU(4)\times U(1)$ -- electroweak model with a scalar decuplet

TL;DR

This paper proposes a neutrino mass model within an $SU(4) imes U(1)$ electroweak framework, utilizing a scalar decuplet and a seesaw mechanism to explain small neutrino masses and their mixing with heavy neutrinos across various mass scales.

Contribution

It introduces a novel $SU(4) imes U(1)$ model with a scalar decuplet for neutrino masses, detailing the mixing with heavy neutrinos and potential experimental signatures.

Findings

Neutrino masses can be explained via a seesaw mechanism with scalar decuplet.

The model predicts heavy neutrinos at various mass scales, including eV-MeV.

Current and future experiments can potentially detect these heavy neutrinos.

Abstract

A neutrino mass model is suggested within an $SU(4)\times U(1)$ -- electroweak theory. The smallness of neutrino masses can be guaranteed by a seesaw mechanism realized through Yukawa couplings to a scalar $SU(4)$-decuplet. In this scheme the light active neutrinos are accompanied by heavy neutrinos, which may have masses at different scales, including those within eV-MeV scales investigated quite intensively in both particle physics and astrophysics/cosmology. The flavour neutrinos are superpositions of light neutrinos and a small fraction of heavy neutrinos with the mixing to be determined by the model's parameters (Yukawa coupling coefficients or symmetry breaking scales). The distribution shape of the Yukawa couplings can be visualized via a model-independent distribution of the neutrino mass matrix elements derived by using the current experimental data. With reference to several current and near future experiments, detectable bounds of these heavy neutrinos at different mass scales are discussed and estimated.