String Theory and the Dark Glueball Problem

TL;DR

This paper investigates cosmological constraints on dark Yang-Mills sectors, highlighting overproduction issues of dark glueballs and exploring potential solutions involving reheating and decay channels, with implications for string models.

Contribution

It provides a detailed analysis of dark glueball overproduction problems and evaluates possible cosmological solutions within string-inspired models.

Findings

Dark glueballs are overproduced in large UV parameter regions.

Preferential reheating into the visible sector can mitigate overproduction.

Decays into axions or moduli are constrained by nucleosynthesis and $\

Abstract

We study cosmological constraints on dark pure Yang-Mills sectors. Dark glueballs are overproduced for large regions of ultraviolet parameter space. The problem may be alleviated in two ways: via a large preferential reheating into the visible sector, motivating certain inflation or modulus decay models, or via decays into axions or moduli, which are strongly constrained by nucleosynthesis and $\Delta N_{\text{eff}}$ bounds. String models frequently have multiple hidden Yang-Mills sectors, which are subject to even stronger constraints due to the existence of multiple dark glueballs.