Asymmetric Dark Matter From Scattering

TL;DR

This paper investigates how dark matter scattering processes in the early universe can generate a chemical potential, influencing the current dark matter density and asymmetry, offering insights into asymmetric dark matter scenarios.

Contribution

It introduces a study of dark matter chemical potential generation solely from DM scatterings and explores its impact on dark matter abundance and composition.

Findings

DM scattering can produce a non-zero chemical potential.

Generated chemical potential affects dark matter asymmetry.

Implications for dark matter relic density and composition.

Abstract

In dark matter (DM) cosmology, the central question is how the present-day density of DM is generated from some initial conditions in the early universe. Different production mechanisms of DM are instrumental in probing DM microphysics in current and future experiments and observations. In this context, thermal dark matter is historically most-studied scenario, in which DM is thermalized with the visible sector in the early universe. Thermalized DM sector is described by visible sector temperature and a chemical potential in general. In particular, a non-zero chemical potential of DM indicates a difference (asymmetry) between particle-antiparticle number densities in the dark sector. In this work, we have studied the generation of DM chemical potential only from DM scatterings and their interplay in the early universe, consequently its effect on the present-day density and the composition of DM.