Combining type I and type II seesaw mechanisms in the minimal 3-3-1 model

TL;DR

This paper proposes a modification to the minimal 3-3-1 model to incorporate both type I and type II seesaw mechanisms, enabling neutrino masses at eV scale with a cutoff scale of a few TeV, and analyzes lepton flavor violation.

Contribution

It introduces a combined seesaw mechanism in the minimal 3-3-1 model, achieving neutrino mass suppression at TeV scales, which was challenging before.

Findings

Neutrino masses at eV scale are achievable with TeV-scale cutoff.

The combined seesaw mechanism yields a mass suppression proportional to $M^5$.

Lepton flavor violation processes like $oldsymbol{ extmu ightarrow e extgamma}$ are analyzed.

Abstract

The minimal 3-3-1 model is perturbative until energies around 4-5TeV, posing a challenge to generate neutrino masses at eV scale, mainly if one aims to take advantage of the seesaw mechanism. As a means to circumvent this problem we propose a modification of the model such that it accommodates the type I and type II seesaw mechanisms altogether. We show that the conjunction of both mechanisms yield a neutrino mass expression suppressed by a high power of the cutoff scale, $M^5$, in its denominator. With such a suppression term we naturally obtain neutrino masses at eV scale when $M$ is around few TeV. We also investigate the size of lepton flavor violation through the process $\mu \rightarrow e\gamma$.