Recent studies indicate that thermally produced dark matter will form highly concentrated, low-mass cusps in the early universe that often survive until the present. While these cusps contain a small fraction of the dark matter, their high density significantly increases the expected gamma-ray flux from dark matter annihilation, particularly in searches of large angular regions. We utilize 14 years of Fermi-LAT data to set strong constraints on dark matter annihilation through a detailed study of the isotropic gamma-ray background, excluding with 95% confidence dark matter annihilation to bbˉ final states for dark matter masses below 120 GeV.
@article{arxiv.2307.13023,
title = {Limits on dark matter annihilation in prompt cusps from the isotropic gamma-ray background},
author = {M. Sten Delos and Michael Korsmeier and Axel Widmark and Carlos Blanco and Tim Linden and Simon D. M. White},
journal= {arXiv preprint arXiv:2307.13023},
year = {2024}
}