TH Cosmo Coffee

# Cold Positrons from Decaying Dark Matter

## by Oscar Vives (U. Valencia)

Wednesday, 25 July 2012 from to (Europe/Zurich)
at CERN ( 4-2-011 - TH common room )
 Description Many models of dark matter contain more than one new particle beyond those in the Standard Model. Often heavier particles decay into the lightest dark matter particle as the Universe evolves. Here we explore the possibilities that arise if one of the products in a (Heavy Particle) $\rightarrow$ (Dark Matter) decay is a positron, and the decay occurs between photon decoupling and the present time. The positrons cool down by scattering off the cosmic microwave background and eventually annihilate when they fall into Galactic potential wells. The resulting 511 keV flux not only places constraints on this class of models but might even be consistent with that observed by the INTEGRAL satellite.