Statistical analysis of supersymmetric dark matter in the minimal supersymmetric standard model after WMAP

We study supersymmetric dark matter in the general flavor diagonal minimal supersymmetric standard model by means of an extensive random scan of its parameter space. We find that, in contrast with the standard minimal supergravity lore, the large majority of viable models features either a Higgsino or a winolike lightest neutralino, and yields a relic abundance well below the Wilkinson Microwave Anisotropy Probe (WMAP) bound. Among the models with neutralino relic density within the WMAP range, Higgsinolike neutralinos are still dominant, though a sizable fraction of binos is also present. In this latter case, coannihilations 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.