SIMP dark matter and its cosmic abundances

TL;DR

This paper reviews the thermal averaging of higher-order dark matter annihilation processes, emphasizing velocity dependence and resonance effects, with specific examples from scalar dark matter in gauged Z3 models.

Contribution

It provides a detailed analysis of thermal averages for 3→2 and higher processes, highlighting velocity dependence and resonance effects in dark matter models.

Findings

Thermal averages of higher-order annihilations depend strongly on dark matter velocity.

Resonance poles significantly influence annihilation cross-sections.

Scalar dark matter in gauged Z3 models exemplifies these effects.

Abstract

We give a review on the thermal average of the annihilation cross-sections for $3\rightarrow 2$ and general higher-order processes. Thermal average of higher order annihilations highly depend on the velocity of dark matter, especially, for the case with resonance poles. We show such examples for scalar dark matter in gauged $Z_3$ models.