PROFILE OF THE DARK MATTER IN OUR GALAXY AND SUPERSYMMETRY

par Dmitri Kazakov (Bogoliubov Laboratory of Th.Phys.)

lundi 18 sept. 2006, 14:00 → 15:00 Europe/Paris

Amphithéâtre

Dark Matter particles are invisible and of unknown nature. One only knows that they dominate the gravitational forces in the Universe. They may self-annihilate each other, thus producing energetic electromagnetic radiation. The key features of such radiation are observed in the public data on diffuse Galactic gamma rays from the EGRET space telescope using a novel analysis technique. The energy spectrum of this extra radiation limits the mass of possible WIMP to the 50-100 GeV range, while the sky maps determine the halo structure. The data show a substructure in the form of a doughnut shaped ring around our galaxy, which is strongly correlated with the ring of stars around our galaxy at distance of 14 kpc and provides the first explanation for the peculiar change of slope of the rotation curve for large radii. The signals of Dark Matter annihilation have statistical significance of more than 10 sigma in comparison with the conventional galactic model. This provides an intriguing hint that it is indeed the signal from Dark matter annihilation and shows that Dark Matter is not so dark after all. This signal is compatible with supersymmetry that suggests that the DM is made of neutralinos, the superpartners of the photon, with the mass around 70 GeV. SUSY interpretation of the DM restricts the allowed region in SUSY parameter space compatible with the WMAP data on energy budget of the Universe. In its turn this choice of parameters of SUSY allows one to predict the mass specrum of superpartners and calculate the cross-sections of their production at LHC which happen to be large enough for their observation.