Leptogenesis without violation of B-L

TL;DR

This paper explores a novel leptogenesis mechanism that generates the universe's baryon asymmetry without requiring Majorana masses or total lepton number violation, relying instead on lepton flavor effects and sphaleron processes.

Contribution

It introduces a leptogenesis scenario without Majorana masses above the electroweak scale, emphasizing lepton flavor effects and sphaleron decoupling as the key factors.

Findings

Baryon asymmetry can be generated without total lepton number violation.

Lepton flavor effects play a crucial role in the asymmetry generation.

The mechanism operates within a framework consistent with Standard Model sphalerons.

Abstract

We study the possibility of generating the observed baryon asymmetry via leptogenesis in the decay of heavy Standard Model singlet fermions which carry lepton number, in a framework without Majorana masses above the electroweak scale. Such scenario does not contain any source of total lepton number violation besides the Standard Model sphalerons, and the baryon asymmetry is generated by the interplay of lepton flavour effects and the sphaleron decoupling in the decay epoch.