Semi-annihilation of Dark Matter

Abstract

The semi-annihilation reaction takes the schematic form psi_i psi_j -> psi_k phi, where psi_i are stable dark matter particles and phi is an unstable state. Such reactions are allowed when dark matter is stabilized by a larger symmetry than just Z_2. They lead to non-trivial dark matter dynamics in the early universe, and the thermal production of the relic particles can be completely controlled by semi-annihilations. This process might also take place today in the Milky Way, enriching the (semi-)annihilation final state spectrum observed in indirect detection experiments.

Comments: 7 pages, 4 figures, 1 table - Talk presented at "Identification of Dark Matter 2010," July 26-30, 2010, Montpellier, France