Large lepton mixing angles from a 4+1-dimensional SU(5) x A(4) domain-wall braneworld model

TL;DR

This paper extends a 4+1D SU(5) braneworld model with A(4) flavor symmetry to naturally generate large lepton mixing angles and neutrino masses, while addressing the vacuum realignment problem through extra-dimensional separation.

Contribution

It introduces an A(4) flavor symmetry into a 4+1D SU(5) braneworld model, enabling realistic lepton mixing and neutrino masses with a solution to the vacuum realignment issue.

Findings

Large lepton mixing angles achieved

Neutrino masses generated from A(4) physics

Vacuum realignment problem solved via extra-dimensional separation

Abstract

We propose an extension of the 4+1D SU(5) domain-wall braneworld of Davies, George and Volkas which includes the addition of a discrete A(4) flavor symmetry. We show that lepton mixing and light Majorana neutrino masses can be generated from the additional A(4) physics while at the same time sufficient parameter freedom can be maintained in the charged fermion sector to produce charged fermion masses and quark mixing naturally from the split fermion mechanism. Importantly, we show that the vacuum realignment problem typical of discrete flavor symmetry models of quark and lepton mixing can be solved by separating the appropriate flavons in the extra dimension, leading to exponentially sensitive suppression of the operators responsible for vacuum realignment.