Cosmological Bounds on Non-Abelian Dark Forces

TL;DR

This paper explores how non-Abelian dark forces, through their dark glueballs and connector operators, influence cosmology and astrophysics, leading to strong constraints or potential dark matter candidates.

Contribution

It provides the first detailed analysis of cosmological evolution, decay processes, and observational constraints for dark glueballs connected to the Standard Model.

Findings

Dark glueball decays affect cosmological observables

Strong limits are set on pure non-Abelian dark forces

Stable dark glueballs could account for dark matter

Abstract

Non-Abelian dark gauge forces that do not couple directly to ordinary matter may be realized in nature. The minimal form of such a dark force is a pure Yang-Mills theory. If the dark sector is reheated in the early universe, it will be realized as a set of dark gluons at high temperatures and as a collection of dark glueballs at lower temperatures, with a cosmological phase transition from one form to the other. Despite being dark, the gauge fields of the new force can connect indirectly to the Standard Model through non-renormalizable operators. These operators will transfer energy between the dark and visible sectors, and they allow some or all of the dark glueballs to decay. In this work we investigate the cosmological evolution and decays of dark glueballs in the presence of connector operators to the Standard Model. Dark glueball decays can modify cosmological and astrophysical observables, and we use these considerations to put very strong limits on the existence of pure non-Abelian dark forces. On the other hand, if one or more of the dark glueballs are stable, we find that they can potentially make up the dark matter of the universe.