A Statistical Analysis of Supersymmetric Dark Matter in the MSSM after WMAP

We study supersymmetric dark matter in the general flavor diagonal MSSM by means of an extensive random scan of its parameter space. We find that, in contrast with the standard mSUGRA lore, the large majority of viable models features either a higgsino or a wino-like lightest neutralino, and yields a relic abundance well below the WMAP bound. Among the models with neutralino relic density within the WMAP range, higgsino-like neutralinos are still dominant, though a sizeable fraction of binos is also present. In this latter case, relic density suppression mechanisms are shown to be essential in order to obtain the correct neutralino abundance. We then carry out a statistical analysis and a general discussion of neutralino dark matter direct detection and of indirect neutralino detection at neutrino telescopes and at antimatter search experiments. We point out that current data exclude only a marginal portion of the viable parameter space, and that models whose thermal relic abundance lies in the WMAP range will be significantly probed only at future direct detection experiments. Finally, we emphasize the importance of relic density enhancement mechanisms for indirect detection perspectives, in particular at future antimatter search experiments.