We examine the cross sections for the elastic scattering of neutralinos χ on nucleons p, n, as functions of m χ 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 m 0 , m 1/2 , and µ and the MSSM Higgs masses treated as dependent parameters. We explore systematically the region of the (m 1/2 , m 0 ) plane where LEP and other accelerator constraints are respected, and the relic neutralino density lies in the range 0.1 ≤ Ω χ h 2 ≤ 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.

We explore the possible cross sections for the elastic scattering of neutralinos on nucleons p,n in the minimal supersymmetric extension of the standard model ͑MSSM͒. Universality of the soft supersymmetrybreaking scalar masses for the Higgs multiplets is not assumed, but the MSSM parameters are nevertheless required to lead consistently to an electroweak vacuum. We explore systematically the region of MSSM parameter space where CERN LEP and other accelerator constraints are respected, and the relic neutralino density lies in the range 0.1р⍀ h 2 р0.3 preferred by cosmology. We also discuss models with ⍀ h 2 Ͻ0.1, in which case we scale the density of supersymmetric dark matter in our galactic halo by ⍀ h 2 /0.1, allowing for the possible existence of some complementary form of cold dark matter. We restrict our attention to tan␤ р10, for which reliable relic-density calculations are available. Within this range of tan␤, we find values of the cross sections that are considerably lower than the present experimental sensitivities. At low neutralino masses, m Շ100 GeV, the cross sections may be somewhat higher than in the constrained MSSM with universal soft Higgs boson masses, though they are generally lower. In the case of large m , the cross sections we find may be considerably larger than in the constrained model, but still well below the present experimental sensitivity.

We compute the four-Fermi neutralino-quark interaction Lagrangian including contributions from the CP violating phases in the MSSM. We find that neutralino-nucleus scattering crosssections relevant for direct detection experiments show a strong dependence on the value of the CP-violating phase associated with the µ parameter, θ µ . In some cases, for a broad range of non-zero θ µ , there are cancellations in the cross-sections which reduce the cross-section by more than an order of magnitude. In other cases, there may be enhancements as one varies θ µ .

A new set of supersymmetric benchmark scenarios has recently been proposed in the context of the constrained MSSM (CMSSM) with universal soft supersymmetry-breaking masses, taking into account the constraints from LEP, b → sγ and g µ − 2. These points have previously been used to discuss the physics reaches of different accelerators. In this paper, we discuss the prospects for discovering supersymmetric dark matter in these scenarios. We consider direct detection through spin-independent and spin-dependent nuclear scattering, as well as indirect detection through relic annihilations to neutrinos, photons, and positrons. We find that several of the benchmark scenarios offer good prospects for direct detection via spin-independent nuclear scattering and indirect detection via muons produced by neutrinos from relic annihilations inside the Sun, and some models offer good prospects for detecting photons from relic annihilations in the galactic centre.

Abstract. Direct and indirect dark matter detection relies on the scattering of the dark matter candidate on nucleons or nuclei. Here, attention is focused on dark matter candidates (neutralinos) predicted in the minimal supersymmetric standard model and its constrained version with universal input soft supersymmetry-breaking masses. Current expectations for elastic scattering cross sections for neutralinos on protons are discussed with particular attention to satisfying all current accelerator constraints as well as insuring a sufficient cosmological relic density to account for the dark matter in the Universe.