Dark Matter Detection Rates In SUGRA Models

Abstract

Direct detection of Milky Way wimps are discussed within the framework of R-parity conserving SUGRA models with grand unification at M_G. Two questions are discussed: what SUGRA models can account for the DAMA data if this data is confirmed, and is the full SUGRA parameter space accessible to future planned detectors. Experimental constraints of the Higgs mass bound, the b-> s\gamma bound, relic density constraints (including all co-annihilation channels), etc. are imposed. In addition, the effect of the possible muon g - 2 anomaly are examined. For mSUGRA, we find that the Higgs mass and b\to s\gamma constraint puts a lower bound m_{1/2} > (300 - 400) GeV (i.e. m_{\tilde\chi^0_1} > (120 - 160) GeV) for \tan\beta < 50, and thus the largest theoretical neutralino-proton cross sections still lie significantly below the DAMA 3\sigma lower bound. (Predictions for \tan\beta> 50 become sensitive to the precise value of m_t and m_b.) If in addition one imposes the muon anomaly constraint, \mu must be positive and an upper bound of m_{1/2}< 850 GeV for \tan\beta < 50 is obtained. More generally, if \mu >0 and m_{1/2} < 1 TeV, the cross sections are >~ 10^{-10} pb, and hence this parameter space would be mostly accessible to planned high sensitivity detectors. For non-minimal SUGRA models, the cross sections can be considerably larger, and a simple SU(5) model with non-universal soft breaking in the Higgs and third generation is seen to give cross sections in the DAMA range for \tan\beta >~ 15 with m_{\tilde\chi^0_1} > 80 GeV, and minimum cross sections >~10^{-10} pb for \mu > 0.