Accidentally Asymmetric Dark Matter.

Pouya Asadi,Gregory W Ridgway,Eric Kuflik,Tracy R Slatyer,Eric David Kramer,Juri Smirnov

doi:10.1103/physrevlett.127.211101

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 candidates. 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 O(1-100) PeV dark quarks, above the usual unitarity bound.

Highlights

In such scenarios, two events in cosmic history can influence the relic abundance: the freeze-out of the interactions that set the constituent quark abundance and the phase transition that converts elementary constituents into composite states
In this Letter we focus on the opposite regime, where the phase transition happens at much lower temperatures than the freeze-out of constituent quarks
This regime has been considered in Refs. [24,25,26,28,30]; the detailed dynamics of the phase transition have never been taken into account

Summary

Introduction

Two events in cosmic history can influence the relic abundance: the freeze-out of the interactions that set the constituent quark abundance and the phase transition that converts elementary constituents into composite states. We find that in a large fraction of the parameter space, the relic abundance is strongly affected by the bubble dynamics; the dark quarks are compressed within contracting pockets of the deconfined phase, leading to a second stage of efficient annihilation. Since mq ≫ Λ, the dark quark abundance freezes out before the phase transition takes place.

Results

Conclusion