Neutrino Mixings and the S4 Discrete Flavour Symmetry

TL;DR

This paper reviews the use of the S4 discrete flavor symmetry in modeling lepton mixing patterns, discussing formalism, phenomenological implications, and compatibility with recent experimental data.

Contribution

It provides a comprehensive overview of S4-based flavor models, highlighting their ability to reproduce observed lepton mixing angles and predict lepton flavor violation.

Findings

S4 models can reproduce the reactor angle consistent with recent data

S4-based models predict lepton flavor violating transitions

The formalism facilitates understanding of flavor symmetry applications

Abstract

Discrete non-Abelian Symmetries have been extensively used to reproduce the lepton mixings. In particular, the S4 group turned out to be suitable to describe predictive mixing patterns, such as the well-known Tri-Bimaximal and the Bimaximal schemes, which all represent possible first approximations of the experimental lepton mixing matrix. We review the main application of the S4 discrete group as a flavour symmetry, first dealing with the formalism and later with the phenomenological implications. In particular, we summarize the main features of flavour models based on S4, commenting on their ability in reproducing a reactor angle in agreement with the recent data and on their predictions for lepton flavour violating transitions.