Constraints on light decaying dark matter candidates from 16 years of INTEGRAL/SPI observations

Abstract

We apply the recently developed analysis of 16 years of INTEGRAL/SPI data including a dark matter spatial template to derive bounds on dark matter candidates lighter than WIMPs (like sterile neutrinos or axion-like particles) decaying into line or continuum electromagnetic final state channels. The bounds obtained are the strongest to date for dark matter masses between $\sim$60 keV and $\sim$16 MeV experiencing two-body decays producing photon lines.

6 pages, 5 figures. Code and supplementary material available at https://zenodo.org/record/7984451. v4: Figures 1, 2, 3 and 4 are revised to correct for error in bounds; conclusions are qualitatively unchanged