Multi-component Dark Sectors: Symmetries, Asymmetries and Conversions

TL;DR

This paper investigates the relic abundance of multi-component dark matter, focusing on symmetries, asymmetries, and conversions, revealing that similar symmetric and asymmetric components are a common outcome with significant phenomenological implications.

Contribution

It provides a comprehensive analysis of how dark matter components' relic abundances are affected by conversions and asymmetries, highlighting the exponential dependence and natural occurrence of similar symmetric and asymmetric components.

Findings

Exponential dependence of heavier components' asymmetries on annihilations and conversions

Similar symmetric and asymmetric components are a natural outcome in many scenarios

Phenomenological implications of multi-component dark matter are discussed

Abstract

We study the relic abundance of several stable particles from a generic dark sector, including the possible presence of dark asymmetries. After discussing the different possibilities for stabilising multi-component dark matter, we analyse the final relic abundance of the symmetric and asymmetric dark matter components, paying special attention to the role of the unavoidable conversions between dark matter states. We find an exponential dependence of the asymmetries of the heavier components on annihilations and conversions. We conclude that having similar symmetric and asymmetric components is a natural outcome in many scenarios of multi-component dark matter. This has novel phenomenological implications, which we briefly discuss.