Asymmetric dark matter, baryon asymmetry and lepton number violation

TL;DR

This paper investigates how lepton number violation affects baryon asymmetry in the early universe within models featuring asymmetric dark matter, showing that certain LNV processes do not erase the baryon asymmetry and linking observable LNV to ADM scenarios.

Contribution

It demonstrates that lepton number violation at accessible energies does not necessarily wash out baryon asymmetry in the presence of a dark sector with a global symmetry, supporting ADM models.

Findings

LNV processes at the TeV scale do not erase baryon asymmetry in ADM scenarios.

Dark matter mass in these models is typically a few GeV or less.

Observation of LNV could support the existence of asymmetric dark matter.

Abstract

We study the effect of lepton number violation (LNV) on baryon asymmetry, generated in the early Universe, in the presence of a dark sector with a global symmetry $U(1)_X$, featuring asymmetric dark matter (ADM). We show that in general LNV, observable at the LHC or in neutrinoless double beta decay experiments, cannot wash out a baryon asymmetry generated at higher scales, unlike in scenarios without such dark sector. An observation of LNV at the TeV scale may thus support ADM scenarios. Considering several models with different types of dark matter (DM), we find that the DM mass is of the order of a few GeV or below in our scenario.