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

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 $2\to 2$ washout processes in type-I leptogenesis and the Sommerfeld-enhanced $2\to 2$ 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.

Comments: 9 pages, 3 figures, comments begrudgingly welcomed. v2: small corrections, references added. v3: minor comments added