Tri-bimaximal Neutrino Mixing and $\theta_{13}$

TL;DR

This paper extends the tri-bimaximal neutrino mixing model to include a non-zero reactor angle $ heta_{13}$ while preserving other mixing angle predictions, using a see-saw mechanism within GUT models with discrete symmetries.

Contribution

It introduces a tri-bimaximal-reactor mixing framework derived from the type I see-saw mechanism with partially constrained sequential dominance in GUT models.

Findings

Proposes a model that includes a non-zero $ heta_{13}$ angle.

Shows how to realize this mixing pattern in GUT models with $A_4$ symmetry.

Maintains predictions for $ heta_{23}$ and $ heta_{12}$ angles.

Abstract

We propose an extension of tri-bimaximal mixing to include a non-zero reactor angle $\theta_{13}$ while maintaining the tri-bimaximal predictions for the atmospheric angle $\theta_{23}=45^o$ and solar angle $\theta_{12}=35^o$. We show how such tri-bimaximal-reactor mixing can arise at leading order from the(type I) see-saw mechanism with partially constrained sequential dominance. Partially constrained sequential dominance can be realized in GUT models with a non-Abelian discrete family symmetry, such as $A_4$, spontaneously broken by flavons with a particular vacuum alignment.