Re-evaluation of the elastic scattering of supersymmetric dark matter

We examine the cross sections for the elastic scattering of neutralinos χ on nucleons p,n, as functions of mχ in the constrained minimal supersymmetric standard model. We find narrow bands of possible values of the cross section, that are considerably lower than some previous estimates. The constrained model is based on the minimal supergravity-inspired framework for the MSSM, with universal scalar and gaugino masses m0,m1/2, and μ and the MSSM Higgs masses treated as dependent parameters. We explore systematically the region of the (m1/2,m0) plane where LEP and other accelerator constraints are respected, and the relic neutralino density lies in the range 0.1≤Ωχh2≤0.3 preferred by cosmology. We update previous discussions of both the spin-independent and -dependent scattering matrix elements on protons and neutrons, using recent analyses of low-energy hadron experiments.