Relic Abundance of Asymmetric Dark Matter

TL;DR

This paper extends the standard symmetric Dark Matter relic abundance calculation to asymmetric Dark Matter, analyzing how asymmetry affects relic density and indirect detection signals, with implications for MeV Dark Matter models.

Contribution

It generalizes the analytic relic abundance calculation to asymmetric Dark Matter and explores the impact of asymmetry on detection signals and model building.

Findings

Asymmetry reduces indirect detection signals from WIMP annihilation.

Higher annihilation cross sections are compatible with observed relic abundance in asymmetric Dark Matter.

The results enable new model constructions for MeV Dark Matter.

Abstract

We investigate the relic abundance of asymmetric Dark Matter particles that were in thermal equilibrium in the early universe. The standard analytic calculation of the symmetric Dark Matter is generalized to the asymmetric case. We calculate the asymmetry required to explain the observed Dark Matter relic abundance as a function of the annihilation cross section. We show that introducing an asymmetry always reduces the indirect detection signal from WIMP annihilation, although it has a larger annihilation cross section than symmetric Dark Matter. This opens new possibilities for the construction of realistic models of MeV Dark Matter.