WMAP data and recent developments in supersymmetric dark matter

Abstract

A brief review is given of the recent developments in the analyses of supersymmetric dark matter. Chief among these is the very accurate determination of the amount of cold dark matter in the universe from analyses using WMAP data. The implications of this data for the mSUGRA parameter space are analyzed. It is shown that the data admits solutions on the hyperbolic branch of the radiative breaking of the electroweak symmetry. A part of the hyperbolic branch lies in the so-called inversion region, where the LSP neutralino χ 1 0 becomes essentially a pure Higgsino and degenerates with the next-to-the-lightest neutralino χ 2 0 and the light chargino χ 1 ± . Thus, some of the conventional signals for the observation of supersymmetry in colliders (e.g., the missing energy signals) do not operate in this region. On the other hand, the inversion region contains a high degree of degeneracy of χ 1 0 , χ 2 0 , χ 1 ± leading to coannihilations, which allow for the satisfaction of the WMAP relic density constraints deep on the hyperbolic branch. Further, an analysis of the neutralino-proton cross sections in this region reveals that this region can still be accessible to dark matter experiments in the future. Constraints from g π−2 and from B s 0 → μ + μ − are discussed. Future prospects are also discussed.