Linear Sigma Dark Matter

TL;DR

This paper proposes a self-interacting dark matter model using QCD-like theories with dark pions, exploring their scattering via the sigma resonance and the role of dark photons in relic abundance, with testable predictions for future experiments.

Contribution

It introduces a novel dark matter model based on a linear sigma framework with a detailed scattering analysis and dark photon interactions, expanding the understanding of self-interacting dark matter.

Findings

Viable parameter space for relic abundance

Dark matter self-interactions consistent with observations

Testable predictions for future dark matter searches

Abstract

We present a model of self-interacting dark matter based on QCD-like theories and inspired by the proximity of $a_0(980\pm 20)$ to the $K\bar{K}(990)$ threshold. Dark matter is comprised of dark pions which self-scatter via the $\sigma$ resonance close to the $\pi\pi$ threshold. While the linear sigma model serves as a qualitative guide, a fully unitary description of the scattering in the strongly coupled regime is given by effective range theory. The introduction of a kinetically mixed dark photon allows the dark pion to either freeze-out or -in. We study the viable parameter space which explains the observed relic abundance while evading all current constraints. Searches for dark matter self interactions at different scales, (in)direct detection signals, and (in)visibly-decaying dark photons will test this model in the near future.