High-energy constraints on the direct detection of MSSM neutralinos

The requirement that the MSSM remain an acceptable effective field theory upto energies beyond the weak scale constrains the sparticle spectrum, and hencethe permissible ranges of cold dark matter neutralino-proton cross sections.Specifically, squarks are generally much heavier than sleptons if no tachyonsare to appear before the GUT scale ~10^16 GeV, or even before 10 TeV. Wedisplay explicitly the allowed ranges of effective squark and slepton masses atthe weak scale, and the cross-section ranges allowed if the MSSM is to remainvalid without tachyons up to 10 TeV or the GUT scale. The allowed areas in thecross section-mass plane for both spin-independent and spin-dependentscattering are significantly smaller than would be allowed if the MSSM wererequired to be valid only around the weak scale. In addition to a reduction inthe maximum cross section, the upper limit on the neutralino mass is greatlyreduced when tachyons are avoided, particularly for smaller values of thesquark masses.Comment: 22 pages, 22 figure