Asymmetric WIMP dark matter

TL;DR

This paper introduces an asymmetric WIMP dark matter framework that bridges the gap between symmetric and asymmetric dark matter models, allowing for diverse masses and annihilation rates while maintaining detectable indirect signals.

Contribution

It explores the effects of primordial asymmetry on dark matter and anti-dark matter populations, revealing a broad parameter space with mixed symmetric and asymmetric characteristics.

Findings

Large parameter regions interpolate between symmetric and asymmetric dark matter.

Dark matter can have a wide range of masses and annihilation cross sections.

Indirect detection signals are not fully suppressed despite asymmetry.

Abstract

In existing dark matter models with global symmetries the relic abundance of dark matter is either equal to that of anti-dark matter (thermal WIMP), or vastly larger, with essentially no remaining anti-dark matter (asymmetric dark matter). By exploring the consequences of a primordial asymmetry on the coupled dark matter and anti-dark matter Boltzmann equations we find large regions of parameter space that interpolate between these two extremes. Interestingly, this new asymmetric WIMP framework can accommodate a wide range of dark matter masses and annihilation cross sections. The present-day dark matter population is typically asymmetric, but only weakly so, such that indirect signals of dark matter annihilation are not completely suppressed. We apply our results to existing models, noting that upcoming direct detection experiments will constrain a large region of the relevant parameter space.