出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We explore a dark-matter model in which there are two dark-matter species nearly degenerate in mass, with e = DM/M ≪ 1. The heavier particle undergoes two-body decay with a half-life t , to the lighter dark-matter particle and a noninteracting massless particle. Unlike previous work on decaying dark matter, we explore the regime t > 100 Myr and non-relativistic kick speeds vk/c = e . Using a set of N-body simulations of isolated dark-matter halos, we show how halos change as a function of t and vk. We find that t < 40 Gyr is ruled out for vk & 20 km s−1 (e & 10−4) when we compare the simulations to observations of dwarf-galaxy- to cluster-mass dark matter halos. We highlight which set of observations should provide better future constraints for decays and other types of dark-matter physics.
