Cosmology and Accelerator Tests of Strongly Interacting Dark Matter

TL;DR

This paper explores how vector mesons influence the cosmology and detection prospects of strongly interacting dark matter models, expanding the viable parameter space and proposing experimental tests.

Contribution

It highlights the dominant role of vector mesons in dark matter freeze-out and suggests new accelerator signals, broadening the understanding of strongly interacting dark matter.

Findings

Vector mesons significantly affect dark matter freeze-out dynamics.

Long-lived vector mesons can produce detectable signals at fixed-target experiments.

The viable mass range for strongly interacting dark matter models is widened.

Abstract

A natural possibility for dark matter is that it is composed of the stable pions of a QCD-like hidden sector. Existing literature largely assumes that pion self-interactions alone control the early universe cosmology. We point out that processes involving vector mesons typically dominate the physics of dark matter freeze-out and significantly widen the viable mass range for these models. The vector mesons also give rise to striking signals at accelerators. For example, in most of the cosmologically favored parameter space, the vector mesons are naturally long-lived and produce Standard Model particles in their decays. Electron and proton beam fixed-target experiments such as HPS, SeaQuest, and LDMX can exploit these signals to explore much of the viable parameter space. We also comment on dark matter decay inherent in a large class of previously considered models and explain how to ensure dark matter stability.