Dark showers from sneaky dark matter

TL;DR

This paper introduces a minimal composite dark matter model with stable dark pions as candidates, where their relic abundance and detection prospects are analyzed, highlighting a GeV mass window and long-lived decay signatures.

Contribution

The paper proposes a novel dark matter model with stable dark pions from a composite sector, emphasizing their relic abundance mechanism and experimental signatures.

Findings

Dark pions are stable due to flavor symmetry, serving as dark matter candidates.

Relic abundance is set by co-scattering or co-annihilation processes.

Model constraints are derived from semi-visible and emerging jet searches.

Abstract

We present a minimal composite dark matter model, based on a $SU(N_d)$ dark sector with $n_f$ dark quarks and a heavy t-channel mediator. For $n_f\geq 4$, the dark flavor symmetry guarantees the stability of a subset of the dark pions, which serve as our dark matter candidates. Their relic abundance is determined by co-scattering or co-annihilation with the remaining dark pions, which are unstable and decay. Due to their degenerate masses, the annihilation cross section is suppressed at low temperatures, thereby avoiding stringent constraints from indirect detection and opening up the GeV mass window. The decaying dark pions are naturally long lived. We obtain limits on the model from semi-visible or emerging jet searches and estimate the reach of future probes.