Direct detection of neutralino dark matter in supergravity

The direct detection of neutralino dark matter is analysed in generalsupergravity scenarios, where non-universal soft scalar and gaugino masses canbe present. In particular, the theoretical predictions for theneutralino-nucleon cross section are studied and compared with the sensitivityof dark matter detectors. We take into account the most recent astrophysicaland experimental constraints on the parameter space, including the currentlimit on B(Bs-> mu+ mu-). The latter puts severe limitations on the dark matterscattering cross section, ruling out most of the regions that would be withinthe reach of present experiments. We show how this constraint can be softenedwith the help of appropriate choices of non-universal parameters which increasethe Higgsino composition of the lightest neutralino and minimise the charginocontribution to the b->s transition.Comment: 27 pages, 22 figure