A new idea for relating the asymmetric dark matter mass scale to the proton mass

TL;DR

This paper introduces a novel mechanism linking the dark matter mass scale to the proton mass via an extended color gauge symmetry and a $ ext{Z}_2$ symmetry, resulting in comparable confinement scales and a testable particle spectrum.

Contribution

It proposes a new theoretical framework connecting visible and dark matter mass scales through an extended gauge symmetry and symmetry breaking, also addressing the strong CP problem.

Findings

Predicts similar confinement scales for QCD and dark sector

Results in a rich TeV-scale particle spectrum

Provides a natural axion solution to the strong CP problem

Abstract

Asymmetric dark matter is a well-motivated approach to explain the apparent coincidence between the relic densities of visible and dark matter, $\Omega_D \simeq 5.4\Omega_b$. A complete explanation requires two components, a relation between the particle masses of the dark and visible matter, and a second relation between the number densities in each sector. In this work, we propose a new mechanism to address the former. We consider an extended $SU(3)_1 \times SU(3)_2$ colour group in the visible sector, with QCD embedded as the diagonal subgroup. A $\mathbb{Z}_2$ exchange symmetry then relates $SU(3)_2$ to a dark, confining $SU(3)_D$ sector. The dark matter is a composite state of dark fermions transforming in the fundamental representation of $SU(3)_D$. The spontaneously broken $\mathbb{Z}_2$ symmetry ultimately leads to a relation between the QCD and dark gauge couplings which, for suitable field content, gives rise to confinement scales of the same order of magnitude. The mechanism leads to a rich particle spectrum above the TeV scale which could be probed at future experiments. The model also naturally includes an axion solution to the strong CP problem.