Direct Detection of Neutralino Dark Matter and the Anomalous Dipole Moment of the Muon

We compare predictions for the spin–independent contribution to the neutralino–proton scattering cross section σχp and for the anomalous magnetic dipole moment of the muon, aμ = (gμ − 2)/2, in models with gravity–mediated supersymmetry breaking. We nearly always find a positive correlation between these two measurables, i.e. scenarios with larger aμ also tend to have larger σχp, but the detailed prediction differs greatly between models. In particular, we find that for the popular mSUGRA scenario with universal soft breaking masses at the scale of Grand Unification, measurements of aμ currently seem more promising. On the other hand, if scalar soft breaking masses at the GUT scale receive sizable contributions from SO(10) D–terms, one often finds scenarios with large σχp but aμ below the currently foreseen sensitivity. A string–inspired model with non–universal scalar spectrum at the GUT scale falls between these two cases.