Dark Matter Assimilation into the Baryon Asymmetry

TL;DR

This paper introduces 'assimilation', a novel dark matter mechanism leveraging baryon asymmetry to produce the correct relic abundance of singlet dark matter, involving heavy states and potential LHC signatures.

Contribution

It proposes a new dark matter production mechanism called assimilation, combining baryon asymmetry with heavy states to explain relic abundance, and explores its implications in supersymmetric models.

Findings

Dark matter can be efficiently destroyed and regenerated via assimilation.

Heavy states carrying baryon asymmetry lead to observable long-lived particles at LHC.

The mechanism successfully explains the relic abundance of singlet dark matter.

Abstract

Pure singlets are typically disfavored as dark matter candidates, since they generically have a thermal relic abundance larger than the observed value. In this paper, we propose a new dark matter mechanism called "assimilation", which takes advantage of the baryon asymmetry of the universe to generate the correct relic abundance of singlet dark matter. Through assimilation, dark matter itself is efficiently destroyed, but dark matter number is stored in new quasi-stable heavy states which carry the baryon asymmetry. The subsequent annihilation and late-time decay of these heavy states yields (symmetric) dark matter as well as (asymmetric) standard model baryons. We study in detail the case of pure bino dark matter by augmenting the minimal supersymmetric standard model with vector-like chiral multiplets. In the parameter range where this mechanism is effective, the LHC can discover long-lived charged particles which were responsible for assimilating dark matter.