Neutrino masses in $SU(5)\times U(1)_F$ with adjoint flavons

TL;DR

This paper proposes a supersymmetric $SU(5)\times U(1)_F$ model that naturally explains neutrino masses and mixings using adjoint flavons, with a unique parameter leading to a predictive neutrino mass matrix structure.

Contribution

It introduces a novel $SU(5)\times U(1)_F$ framework with adjoint flavons that yields calculable neutrino masses and mixings, and ensures R-parity as an accidental symmetry.

Findings

Neutrino masses are generated via the seesaw mechanism with hierarchical heavy states.

The model predicts a parameter-independent structure for the light neutrino mass matrix.

R-parity arises naturally as an exact accidental symmetry.

Abstract

We present a $SU(5)\times U(1)_F$ supersymmetric model for neutrino masses and mixings that implements the seesaw mechanism by means of the heavy SU(2) singlets and triplets states contained in three adjoints of SU(5). We discuss how Abelian $U(1)_F$ symmetries can naturally yield non-hierarchical light neutrinos even when the heavy states are strongly hierarchical, and how it can also ensure that $R$--parity arises as an exact accidental symmetry. By assigning two flavons that break $U(1)_F$ to the adjoint representation of SU(5) and assuming universality for all the fundamental couplings, the coefficients of the effective Yukawa and Majorana mass operators become calculable in terms of group theoretical quantities. There is a single free parameter in the model, however, at leading order the structure of the light neutrinos mass matrix is determined in a parameter independent way.