Exploring active-sterile neutrino mixings models in MES mechanism using modular $S_3$ symmetry

TL;DR

This paper investigates minimal extended seesaw models with one sterile neutrino using modular $S_3$ symmetry, classifying models based on symmetry assignments, and fitting neutrino oscillation data and cosmological bounds.

Contribution

It introduces a classification of active-sterile neutrino models within a modular $S_3$ symmetry framework and identifies two models consistent with experimental data.

Findings

Two models fit neutrino oscillation data at 3σ.

Models comply with the Planck cosmological bound on neutrino masses.

Best-fit parameters are obtained via $ ext{min}\, ext{chi}^2$ analysis.

Abstract

We study the minimal extended seesaw mechanism with one sterile neutrino in a 3+1 framework using modular $S_3$ symmetry. The active-sterile neutrino models are classified based on the assignments of $S_3$ representations and modular weights of the left-handed lepton doublets, triplet right-handed neutrino, and sterile neutrino. No scalar flavons are considered, and the flavor symmetry is broken by the vacuum expectation value (vev) of the modulus $\tau$. For a particular set of representations of the Leptons and Higgs field, we obtain eleven (11) different models based on different modular weights of charged lepton $(k_L)$ and right-handed neutrino ($k_N$). Out of these, we consider two models, which are discriminated by carrying out the numerical analysis so that the parameter space in each model can fit the latest neutrino oscillation data at 3$\sigma$. The Planck cosmological bound on the upper limit of the sum of the active neutrino masses $\sum m_i <0.12$eV is also considered. Finally, the best-fit parameters of the neutrino observables and model predictions are evaluated using the minimum $\chi^2$ analysis.