A4xSU(5) SUSY GUT of Flavour with Trimaximal Neutrino Mixing

TL;DR

This paper develops an SU(5) SUSY GUT model incorporating A4 family symmetry that naturally produces trimaximal neutrino mixing, accommodating the observed large reactor angle and providing specific sum rule bounds on mixing deviations.

Contribution

It presents a novel SUSY GUT framework based on A4 symmetry that explains trimaximal neutrino mixing and predicts bounds on mixing parameter deviations.

Findings

Model predicts large reactor angle consistent with experiments.

Derives sum rule bounds relating mixing deviations and CP phase.

Links neutrino mixing patterns to GUT and family symmetry structures.

Abstract

Recent T2K, MINOS and Double CHOOZ results, together with global fits of mixing parameters, indicate a sizeable reactor angle theta13 ~ 8 deg which, if confirmed, would rule out tri-bimaximal (TB) lepton mixing. Recently two of us studied the vacuum alignment of the Altarelli-Feruglio A4 family symmetry model including additional flavons in the 1' and 1" representations, leading to so-called "trimaximal" neutrino mixing and allowing a potentially large reactor angle. Here we show how such a model may arise from a Supersymmetric (SUSY) Grand Unified Theory (GUT) based on SU(5), leading to sum rule bounds |s| < thetaC/3, |a| < (r + thetaC/3)|cos delta|/2, where s,a,r parameterise the solar, atmospheric and reactor angle deviations from their TB mixing values, delta is the CP violating oscillation phase, and thetaC is the Cabibbo angle.