SEARCH FOR ANNUAL AND DAILY DARK-MATTER MODULATIONS WITH GE DETECTORSAT BAKSAN

An energy threshold of 2 keV was achieved for the 1-kg HP Ge detector in a long-term experiment aimed at searches for cold-dark-matter (CDM) particles. Data from two (Ge-76 and natural Ge) detectors were accumu lated and analyzed for a period from May 1995 to March 1997. The effec tive passive and active shielding, together with pulse-shape discrimin ation, allowed one to achieve a background of 0.26 count/(kg keV d) fo r both detectors. New restrictions on the masses of weakly interacting massive particles (WIMP) and on the cross section for their elastic s cattering on nuclei are obtained. The Dirac neutrino as a WIMP is rule d out in the range 13 GeV-4.5 TeV, Annual and daily modulations of the CDM signal are investigated. The possibility of detecting CDM particl es by means of their inelastic interaction with Ge-73 is considered.