Selfish Dark Matter

TL;DR

This paper introduces a novel mechanism for generating dark matter asymmetry from a particle asymmetry in another sector, enabling extremely light dark matter particles without requiring annihilation of the symmetric component.

Contribution

It proposes a new asymmetry transfer mechanism for baryogenesis in asymmetric dark matter models, allowing for very light dark matter and eliminating the need for symmetric component annihilation.

Findings

Dark matter can be much lighter than an eV.

The mechanism allows asymmetric dark matter without symmetric component annihilation.

Potential signals in direct detection, LHC, B-factories, and beam dump experiments.

Abstract

We present a mechanism where a particle asymmetry in one sector is used to generate an asymmetry in another sector. The two sectors are not coupled through particle number violating interactions and are not required to be in thermal contact with each other. When this mechanism is applied to baryogenesis in asymmetric dark matter models, we find that the dark matter particles can be extremely light, e.g. much lighter than an eV, and that in some cases there is no need to annihilate away the symmetric component of dark matter. We discuss a concrete realization of the mechanism with signals in direct detection, at the LHC, at $B$-factories or future beam dump experiments.