On Gaugino Contributions to Soft Leptogenesis

TL;DR

This paper investigates how soft supersymmetry-breaking gaugino masses influence CP violation in right-handed sneutrino decays, highlighting the importance of thermal effects for generating the observed baryon asymmetry.

Contribution

It provides a detailed analysis of gaugino-induced CP violation in sneutrino decays, including thermal corrections, revealing conditions under which these effects can explain baryogenesis.

Findings

Exact cancellation of CP asymmetries at T=0 up to second order.

Thermal effects can induce sizeable CP violation.

Gaugino contributions can produce the observed baryon asymmetry.

Abstract

We study the contributions to CP violation in right-handed sneutrino decays induced by soft supersymmetry-breaking gaugino masses including flavour effects and paying special attention to the role of thermal corrections. Using a field-theoretical as well as a quantum mechanical approach we compute the CP asymmetries and we conclude that for all the soft-supersymmetry breaking sources of CP violation considered, an exact cancellation between the asymmetries produced in the fermionic and bosonic channels occurs at T=0 up to second order in soft supersymmetry-breaking parameters. Once thermal effects are included the new sources of CP violation induced by supersymmetry-breaking gaugino masses can be sizeable and they can produce the observed baryon asymmetry for conventional values of the B parameter.