Search for Dark Matter in the sky

Abstract

The detection of γ‐rays, antiprotons and positrons due to pair annihilation of dark matter particles in the Milky Way halo is a viable indirect technique to search for signatures of supersymmetric dark matter where the major challenge is the discrimination of the signal from the background generated by standard production mechanisms. The new PAMELA antiproton data are consistent with the standard secondary production and this allows us to constrain exotic contribution to the spectrum due to neutralino annihilations. In particular, we show that in the framework of minimal supergravity (mSUGRA), in a clumpy halo scenario (with dumpiness factor⩾10) and for large values of tan(β)⩾55, almost all the parameter space allowed by WMAP is excluded. Instead the PAMELA positron fraction data exhibit an excess that it is very difficult to explain with secondary production. The Fermi‐LAT experiment recently reported high precision measurements of the spectrum of cosmic‐ray electrons‐plus‐positrons (CRE) between 20 GeV ...