Modular $A_4$ invariance and leptogenesis

TL;DR

This paper explores a modular $A_4$ symmetric model with three right-handed neutrinos that explains lepton mass hierarchies, mixing patterns, and successfully accounts for the universe's baryon asymmetry through leptogenesis.

Contribution

It introduces a modular $A_4$ symmetry-based model that links neutrino properties with baryon asymmetry, providing testable predictions for future experiments.

Findings

Right-handed neutrino masses around 10^{13} GeV.

Baryon asymmetry sign depends on neutrino mixing angles and CP phases.

Model explains lepton mass hierarchies and mixing patterns.

Abstract

We consider a model with three right-handed neutrinos in which Yukawa coupling constants and Majorana masses are obtained by requiring the modular $A_4$ symmetry. It has been shown that the model can explain mass hierarchies and mixing patterns of charged leptons and neutrinos with the seesaw mechanism. In this article we investigate the leptogenesis by decays of right-handed neutrinos in this model. It is shown that masses of right-handed neutrinos are about $10^{13}$ GeV in order to account for the observed baryon asymmetry of the universe. Furthermore, the positive sign of the baryon asymmetry is obtained only for the limited ranges of mixing angles and CP violation phases of active neutrinos, which can be tested by future neutrino experiments.