Inelastically Decoupling Dark Matter

TL;DR

This paper introduces the iELDER dark matter candidate, a light, cold relic whose abundance is set by inelastic scattering freeze-out and self-annihilations, with potential for detection in future experiments.

Contribution

It proposes a novel dark matter model based on inelastic decoupling and self-annihilations, supported by toy and QCD-like models, expanding detection prospects.

Findings

iELDER dark matter is in the MeV–GeV mass range.

The model predicts significant self-annihilations.

Detection prospects are promising with new benchmarks.

Abstract

We present a new dark matter candidate, the `inELastically DEcoupling Relic' (iELDER), which is a cold thermal relic whose abundance is determined by the freeze out of its inelastic scattering off of bath particles in the presence of $3\to2$ self-annihilations. The dark matter is predicted to be light, in the $O(\mathrm{MeV}-\mathrm{GeV})$ range, with significant self-annihilations and very weak inelastic couplings to ordinary matter. We demonstrate iELDER dark matter using a $Z_3$-symmetric toy model as well as QCD-like pion theories-the latter showing promising prospects for detection and providing a new benchmark for future searches.