Neutralino dark matter detection in split supersymmetry scenarios

We study the phenomenology of neutralino dark matter within generic supersymmetric scenarios where the gaugino and higgsino masses are much lighter than the scalar soft breaking masses (split supersymmetry). We consider a low-energy model-independent approach and show that the guidelines in the definition of this general framework come from cosmology, which forces the lightest neutralino to have a mass smaller than 2.2 TeV. The testability of the framework is addressed by discussing all viable dark matter detection techniques. Current data on cosmic rays antimatter, gamma-rays and on the abundance of primordial Li-6 already set significant constraints on the parameter space. Complementarity among future direct detection experiments, indirect searches for antimatter and with neutrino telescopes, and tests of the theory at future accelerators, such as the LHC and a NLC, is highlighted. In particular, we study in detail the regimes of wino-higgsino mixing and bino-wino transition, which have been most often neglected in the past. We emphasize that our analysis may apply to more general supersymmetric models where scalar exchanges do not provide the dominant contribution to annihilation rates. (c) 2005 Elsevier B.V. All rights reserved.