On Bimaximal Neutrino Mixing and GUT's

TL;DR

This paper reviews models of neutrino mixing, emphasizing Bimaximal Mixing with discrete symmetries, and explores two new GUT-based models, comparing symmetry-driven approaches to chance-based ones like Anarchy.

Contribution

It introduces two novel GUT models based on $SU(5)$ and $SO(10)$ that realize Bimaximal Mixing with discrete symmetries and discusses their phenomenological implications.

Findings

Bimaximal Mixing can be implemented with $S_4$ symmetry.

GUT models can naturally realize quark-lepton complementarity.

New $SU(5)$ and $SO(10)$ models demonstrate specific phenomenological features.

Abstract

We briefly discuss the present status of models of neutrino mixing. Among the existing viable options we review the virtues of Bimaximal Mixing (that could be implemented by an $S_4$ discrete symmetry), corrected by terms arising from the charged lepton mass diagonalization. In particular in a GUT formulation the property of quark lepton "weak" complementarity can be naturally realized. We discuss in some detail two new versions of particular GUT models, one based on $SU(5)$ and one on $SO(10)$ and the associated phenomenology. We compare these approaches based on symmetry to models based on chance, like Anarchy or $U(1)_{FN}$.