# Leptogenesis with perturbations in type-II and type-III seesaw models

## TL;DR

This paper explores how density perturbations enhance the baryon asymmetry in type-II and type-III leptogenesis models.

## Contribution

The study extends acoustically driven freeze-out calculations to type-II and type-III seesaw models, revealing novel enhancements in baryon asymmetry.

## Key findings

- Acoustically driven freeze-out enhances baryon asymmetry in type-II and type-III leptogenesis.
- CP conserving gauge annihilations suppress heavy particle yields in these models.
- Enhancements occur even in the weak washout regime, unlike in type-I leptogenesis.

## Abstract

Density perturbations have recently been shown to lead to a novel effect in the freeze-out of heavy particles called “acoustically driven freeze-out.” This leads to an enhancement in the yield in standard leptogenesis. We extend this calculation to include \documentclass[12pt]{minimal}
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\begin{document}$$2 \rightarrow 2$$\end{document}2→2 washout processes in type-I leptogenesis and the Sommerfeld-enhanced \documentclass[12pt]{minimal}
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\begin{document}$$2 \rightarrow 2$$\end{document}2→2 gauge annihilations in type-II and type-III leptogenesis. These CP conserving gauge annihilations suppress the yield of heavy particles sourcing the asymmetry. We show the acoustically driven freeze-out leads to novel enhancements in the baryon asymmetry in type-II and type-III leptogenesis, already in the weak washout regime, in contrast with type-I leptogenesis.