Dirac Leptogenesis with a Non-anomalous $U(1)^{\prime}$ Family Symmetry

TL;DR

This paper introduces a Dirac leptogenesis model utilizing a non-anomalous $U(1)^{\

Contribution

It presents a novel framework combining a gauged family symmetry with the Froggatt-Nielsen mechanism for Dirac leptogenesis without additional chiral fermions.

Findings

Achieves realistic fermion masses and mixing angles.

Predicts naturally suppressed Dirac neutrino masses.

Generates sufficient baryon asymmetry via leptogenesis.

Abstract

We propose a model for Dirac leptogenesis based on a non-anomalous $U(1)^{\prime}$ gauged family symmetry. The anomaly cancellation conditions are satisfied with no new chiral fermions other than the three right-handed neutrinos, giving rise to stringent constraints among the charges. Realistic masses and mixing angles are obtained for all fermions. The model predicts neutrinos of the Dirac type with naturally suppressed masses. Dirac leptogenesis is achieved through the decay of the flavon fields. The cascade decays of the vector-like heavy fermions in the Froggatt-Nielsen mechanism play a crucial role in the separation of the primodial lepton numbers. We find that a large region of parameter space of the model gives rise to a sufficient cosmological baryon number asymmetry through Dirac leptogenesis.