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→2 self-annihilations. The dark matter is predicted to be light, in the O(MeV−GeV) range, with significant self-annihilations and very weak inelastic couplings to ordinary matter. We demonstrate iELDER dark matter using a Z3-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.
@article{arxiv.2508.04772,
title = {Inelastically Decoupling Dark Matter},
author = {Ronny Frumkin and Yonit Hochberg and Eric Kuflik and Binyamin Vilk},
journal= {arXiv preprint arXiv:2508.04772},
year = {2025}
}