Accidentally Asymmetric Dark Matter

TL;DR

This paper explores how a first-order phase transition in a confining dark sector with heavy quarks can produce the correct dark matter abundance, surpassing traditional unitarity bounds through a novel annihilation mechanism.

Contribution

It introduces a new scenario where dark matter arises from a confining dark sector with a phase transition, leading to a suppressed abundance determined by local asymmetries.

Findings

Dark matter can be composed of 1-100 PeV dark quarks.

A phase transition causes a second annihilation stage, reducing dark quark abundance.

The model explains the observed dark matter density with heavy dark quarks.

Abstract

We study the effect of a first-order phase transition in a confining $SU(N)$ dark sector with heavy dark quarks. The baryons of this sector are the dark matter candidate. During the confinement phase transition the heavy quarks are trapped inside isolated, contracting pockets of the deconfined phase, giving rise to a second stage of annihilation that dramatically suppresses the dark quark abundance. The surviving abundance is determined by the local accidental asymmetry in each pocket. The correct dark matter abundance is obtained for $\mathcal{O}(1-100)$ PeV dark quarks, above the usual unitarity bound.