Leptogenesis in an SU(5) x A5 Golden Ratio Flavour Model

TL;DR

This paper modifies a flavor model based on SU(5) x A5 symmetry to successfully generate the observed baryon asymmetry via leptogenesis while maintaining compatibility with neutrino oscillation data.

Contribution

It introduces a minimal modification to an existing flavor model, enabling it to produce sufficient baryon asymmetry without losing agreement with neutrino observations.

Findings

Model achieves successful leptogenesis with minimal parameters.

Only normal neutrino mass ordering is compatible.

Introduction of one NLO operator aligns predictions with current data.

Abstract

In this paper we discuss a minor modification of a previous SU(5) x A5 flavour model which exhibits at leading order golden ratio mixing and sum rules for the heavy and the light neutrino masses. Although this model could predict all mixing angles well it fails in generating a sufficient large baryon asymmetry via the leptogenesis mechanism. We repair this deficit here, discuss model building aspects and give analytical estimates for the generated baryon asymmetry before we perform a numerical parameter scan. Our setup has only a few parameters in the lepton sector. This leads to specific constraints and correlations between the neutrino observables. For instance, we find that in the model considered only the neutrino mass spectrum with normal mass ordering and values of the lightest neutrino mass in the interval 10-18 meV are compatible with the current data on the neutrino oscillation parameters. With the introduction of only one NLO operator, the model can accommodate successfully simultaneously even at 1$\sigma$ level the current data on neutrino masses, on neutrino mixing and the observed value of the baryon asymmetry.