Leptogenesis from Soft Supersymmetry Breaking (Soft Leptogenesis)

TL;DR

Soft leptogenesis is a mechanism where CP violation from soft supersymmetry-breaking terms generates a lepton asymmetry, which then leads to the observed baryon asymmetry of the universe, emphasizing thermal effects and flavor dynamics.

Contribution

This paper reviews the theoretical framework of soft leptogenesis, highlighting the role of CP violation, thermal corrections, and flavor effects in generating the baryon asymmetry.

Findings

CP-violating phases in soft terms drive lepton asymmetry

Thermal corrections significantly enhance leptogenesis efficiency

High-temperature $R$-genesis mechanism links initial asymmetry to baryon asymmetry

Abstract

Soft leptogenesis is a scenario in which the cosmic baryon asymmetry is produced from a lepton asymmetry generated in the decays of heavy sneutrinos (the partners of the singlet neutrinos of the seesaw) and where the relevant sources of CP violation are the complex phases of soft supersymmetry-breaking terms. We explain the motivations for soft leptogenesis, and review its basic ingredients: the different CP-violating contributions, the crucial role played by thermal corrections, and the enhancement of the efficiency from lepton flavour effects. We also discuss the high temperature regime $T > 10^7$ GeV in which the cosmic baryon asymmetry originates from an initial asymmetry of an anomalous $R$-charge, and soft leptogenesis reembodies in $R$-genesis.