Initial scales, supersymmetric dark matter, and variations of neutralino-nucleon cross sections

The neutralino-nucleon cross section in the context of the MSSM with universal soft supersymmetry-breaking terms is compared with the limits from dark matter detectors. Our analysis is focused on the stability of the corresponding cross sections with respect to variations of the initial scale for the running of the soft terms, finding that the smaller the scale is, the larger the cross sections become. For example, by taking ${10}^{10-12}\hspace{0.5em}\mathrm{GeV}$ rather than $M_{\mathrm{GUT}},$ which is a more sensible choice, in particular in the context of some superstring models, we find extensive regions in the parameter space with cross sections in the range of ${10}^{-6}–{10}^{-5}\hspace{0.5em}\mathrm{pb},$ i.e., where current dark matter experiments are sensitive. For instance, this can be obtained for $\tan \beta \gtrsim 3.$