Interpreting the recent results on direct searches for dark matter particles in terms of relic neutralinos

Abstract

The most recent results from direct searches for dark matter particles in the Galactic halo are examined in terms of an effective minimal supersymmetric extension of the standard model at the electroweak scale without unification of gaugino masses. We show that the annual-modulation effect at $8.2\ensuremath{\sigma}$ C.L. recently presented by the DAMA Collaboration, as the result of a combined analysis of the DAMA/NaI and the DAMA/LIBRA experiments for a total exposure of 0.82 ton yr, fits remarkably well with what is expected for relic neutralinos for a wide variety of weakly interacting massive particle distribution functions. Bounds derivable from other measurements of direct searches for dark matter particles are analyzed. We stress the role played by the uncertainties affecting the neutralino-quark couplings arising from the involved hadronic quantities. We also examine how present data on cosmic antiprotons can help in constraining the neutralino configurations selected by the DAMA effect, in connection with the values of the astrophysical parameters. Perspectives for measurements of antideuterons, possibly produced in the Galactic halo by self-annihilation of neutralinos belonging to the DAMA configurations, are examined. Finally, we discuss how findings at the LHC would impact on these issues.