Dark Matter Freeze-out via Catalyzed Annihilation

TL;DR

This paper introduces a novel dark matter freeze-out mechanism where annihilation is catalyzed, leading to polynomial depletion of dark matter density, applicable to secluded dark sectors with potential for enhanced indirect detection signals.

Contribution

It proposes a new paradigm of dark matter freeze-out via catalyzed annihilation, differing from traditional exponential depletion models.

Findings

Dark matter depletion proceeds polynomially, not exponentially.

Compatible with CMB and BBN constraints.

Potential for enhanced indirect detection signals.

Abstract

We present a new paradigm of dark matter freeze-out, where the annihilation of dark matter particles is catalyzed. We discuss in detail the regime that the depletion of dark matter proceeds via $2\chi \to 2A'$ and $3A' \to 2\chi$ processes, in which $\chi$ and $A'$ denote dark matter and the catalyst respectively. In this regime, the dark matter number density is depleted polynomially rather than exponentially (Boltzmann suppression) as in classic WIMPs and SIMPs. The paradigm applies for a secluded weakly interacting dark sector with a dark matter in the $\text{MeV-TeV}$ mass range. The catalyzed annihilation paradigm is compatible with CMB and BBN constraints, with enhanced indirect detection signals.