Wash-Out in N_2-dominated leptogenesis

TL;DR

This paper investigates how interactions after leptogenesis can diminish the generated baryon asymmetry, using detailed Boltzmann equations with quantum effects to refine the understanding of wash-out processes.

Contribution

It presents a comprehensive analysis of wash-out effects in N2-dominated leptogenesis, incorporating quantum statistical factors and scattering processes for more accurate predictions.

Findings

Wash-out is significantly affected by scatterings with top quarks.

Quantum statistical factors enhance the wash-out effect.

The study constrains parameter space for successful leptogenesis.

Abstract

We study the wash-out of a cosmological baryon asymmetry produced via leptogenesis by subsequent interactions. Therefore we focus on a scenario in which a lepton asymmetry is established in the out-of-equilibrium decays of the next-to-lightest right-handed neutrino. We apply the full classical Boltzmann equations without the assumption of kinetic equilibrium and including all quantum statistical factors to calculate the wash-out of the lepton asymmetry by interactions of the lightest right-handed state. We include scattering processes with top quarks in our analysis. This is of particular interest since the wash-out is enhanced by scatterings and the use of mode equations with quantum statistical distribution functions. In this way we provide a restriction on the parameter space for this scenarios.