IMPLICATIONS OF LEP ON LABORATORY SEARCHES FOR DARK-MATTER NEUTRALINOS

We discuss how the parameter space of the Minimal Supersymmetric extension of the Standard Model could be probed by future searches for neutralinos with laboratory Dark Matter detectors of a given level of sensitivity. We take into account all the constraints already imposed on model parameters by negative searches for supersymmetry at LEPI, restricting our attention to neutralinos lighter than the W-boson. We find that at a level of sensitivity of 0.1 (kg.day)-1 targets of heavy nuclei would probe much more of the remaining parameter space than would targets of light nuclei. However, at a level of sensitivity of 0.01 (kg.day)-1, a target of heavy nuclei combined with a target of light nuclei such as F-19 would allow exploration of more parameter space than either one alone. We then consider the impact that a negative search for supersymmetry at LEPII would have on these conclusions. We find that when all the constraints that such searches would imply are imposed on model parameters, at a level of sensitivity of 0.1 (kg.day)-1 even targets of heavy nuclei would probe only a small fraction of the allowed parameter space, and at a level of sensitivity of 0.01 (kg.day)-1 a target of heavy nuclei would allow exploration of much more parameter space than a target of light nuclei. Our conclusions are generic to the extent that the large variety of nuclei that we consider cover the range of possibilities.