Effects of reheating on leptogenesis

TL;DR

This paper investigates how reheating after inflation affects leptogenesis, demonstrating that non-thermal production of right-handed neutrinos can significantly enhance baryon asymmetry, potentially relaxing temperature constraints.

Contribution

It provides a detailed numerical analysis showing that non-thermal leptogenesis can produce larger asymmetries than thermal scenarios under certain conditions.

Findings

Asymmetry can be two orders of magnitude larger in non-thermal leptogenesis.

Reheating temperature T_{RH} comparable to neutrino mass M_1 enhances asymmetry.

Lower baryogenesis temperature limits can be relaxed in non-thermal scenarios.

Abstract

We study the evolution of a cosmological baryon asymmetry in leptogenesis when the right-handed neutrinos are produced in inflaton decays. By performing a detailed numerical study over a broad range of inflaton-neutrino couplings we show that the resulting asymmetry can be larger by two orders of magnitude or more than in thermal leptogenesis, if the reheating temperature T_{RH} is of the same order as the right-handed neutrino mass M_1. Hence, the lower limit on the baryogenesis temperature obtained in thermal leptogenesis can be relaxed accordingly.