Enhancement of dark matter relic density from the late time dark matter conversions

TL;DR

This paper shows that interactions between multiple dark matter components can lead to late-time conversions, boosting the relic density of lighter components and potentially explaining indirect detection signals.

Contribution

It introduces a novel mechanism where dark matter conversions at late times enhance relic density, offering an alternative explanation for indirect detection excesses.

Findings

Late-time dark matter conversions increase relic density of light components.

Enhanced relic density can match cosmological observations.

Potential to explain indirect detection signals.

Abstract

We demonstrate that if the dark matter (DM) in the Universe contains multiple components,the interactions between the DM components may induce DM conversions. It is then possible that the lightest DM component with an annihilation cross section much larger than that of the typical weakly interacting massive particle (WIMP) can obtain a relic density in consistent with the cosmological observations, due to an enhancement from the DM conversion process at late time after the thermal decoupling. This provides an alternative source of large boost factor required to explain the excesses reported by the recent DM indirect search experiments.