Abstract
We propose a novel framework where light (sub-GeV) dark matter (DM) is detectable with future MeV -ray telescopes without conflicting with cosmic microwave background (CMB) data. The stable DM particle has a very low thermal relic abundance due to its large pair-annihilation cross section. The DM number density is stored in a slightly heavier, metastable partner with suppressed pair-annihilation rates, that does not perturb the CMB, and whose late-time decays fill the Universe with DM particles. We provide explicit, model-independent realizations for this framework, and discuss constraints on late-time decays, and thus on parameters of this setup, from CMB, big bang nucleosynthesis, and large scale structure.
- Received 12 June 2018
- Revised 16 July 2018
DOI:https://doi.org/10.1103/PhysRevLett.121.071101
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.
Published by the American Physical Society