Tri-Bimaximal Neutrino Mixing and Discrete Flavour Symmetries

TL;DR

This paper reviews how non-Abelian discrete groups, especially A4, are used to model neutrino mixing patterns like Tri-Bimaximal mixing, discussing their successes, challenges, and phenomenological implications including quark extensions.

Contribution

It provides a comprehensive review of discrete flavor symmetry models for neutrino mixing, highlighting recent developments and the impact of new experimental data on these models.

Findings

Recent measurements of θ_13 favor models with larger corrections to mixing angles.

Models based on A4 and other finite groups can naturally accommodate observed neutrino mixing.

Discussion of the advantages and issues of Tri-Bimaximal mixing models in light of experimental data.

Abstract

We review the application of non-Abelian discrete groups to Tri-Bimaximal (TB) neutrino mixing, which is supported by experiment as a possible good first approximation to the data. After summarizing the motivation and the formalism, we discuss specific models, mainly those based on A4 but also on other finite groups, and their phenomenological implications, including the extension to quarks. The recent measurements of \theta_13 favour versions of these models where a suitable mechanism leads to corrections to \theta_13 that can naturally be larger than those to \theta_12 and \theta_23. The virtues and the problems of TB mixing models are discussed, also in connection with lepton flavour violating processes, and the different approaches are compared.