We report results of a search for weakly interacting massive particles (WIMPS) with the silicon detectors of the CDMS II experiment. This blind analysis of 140.2 kg day of data taken between July ...2007 and September 2008 revealed three WIMP-candidate events with a surface-event background estimate of 0.41(-0.08)(+0.20)(stat)(-0.24)(+0.28)(syst). Other known backgrounds from neutrons and 206Pb are limited to <0.13 and <0.08 events at the 90% confidence level, respectively. The exposure of this analysis is equivalent to 23.4 kg day for a recoil energy range of 7-100 keV for a WIMP of mass 10 GeV/c2. The probability that the known backgrounds would produce three or more events in the signal region is 5.4%. A profile likelihood ratio test of the three events that includes the measured recoil energies gives a 0.19% probability for the known-background-only hypothesis when tested against the alternative WIMP+background hypothesis. The highest likelihood occurs for a WIMP mass of 8.6 GeV/c2 and WIMP-nucleon cross section of 1.9×10(-41) cm2.
We report results from a reanalysis of data from the Cryogenic Dark Matter Search (CDMS II) experiment at the Soudan Underground Laboratory. Data taken between October 2006 and September 2008 using ...eight germanium detectors are reanalyzed with a lowered, 2 keV recoil-energy threshold, to give increased sensitivity to interactions from weakly interacting massive particles (WIMPs) with masses below ∼10 GeV/c(2). This analysis provides stronger constraints than previous CDMS II results for WIMP masses below 9 GeV/c(2) and excludes parameter space associated with possible low-mass WIMP signals from the DAMA/LIBRA and CoGeNT experiments.
The CDMS and EDELWEISS collaborations have combined the results of their direct searches for dark matter using cryogenic germanium detectors. The total data set represents 614 kg/days equivalent ...exposure. A straightforward method of combination was chosen for its simplicity before data were exchanged between experiments. The results are interpreted in terms of limits on spin-independent weakly interacting, massive particle (WIMP)-nucleon cross section. For a WIMP mass of 90 GeV/c{sup 2}, where this analysis is most sensitive, a cross section of 3.3 x 10{sup -44} cm{sup 2} is excluded at 90% C.L. At higher WIMP masses, the combination improves the individual limits, by a factor 1.6 above 700 GeV/c{sup 2}. Alternative methods of combining the data provide stronger constraints for some ranges of WIMP masses and weaker constraints for others.
We report results from a reanalysis of data from the Cryogenic Dark Matter Search (CDMS II) experiment at the Soudan Underground Laboratory. Data taken between October 2006 and September 2008 using ...eight germanium detectors are reanalyzed with a lowered, 2 keV recoil-energy threshold, to give increased sensitivity to interactions from weakly interacting massive particles (WIMPs) with masses below {approx}10 GeV/c{sup 2}. This analysis provides stronger constraints than previous CDMS II results for WIMP masses below 9 GeV/c{sup 2} and excludes parameter space associated with possible low-mass WIMP signals from the DAMA/LIBRA and CoGeNT experiments.
We report results from the Cryogenic Dark Matter Search at the Soudan Underground Laboratory (CDMS II) featuring the full complement of 30 detectors. A blind analysis of data taken between October ...2006 and July 2007 sets an upper limit on the weakly interacting massive particle (WIMP) nucleon spin-independent cross section of 6.6x10{sup -44} cm{sup 2} (4.6x10{sup -44} cm{sup 2} when combined with previous CDMS II data) at the 90% confidence level for a WIMP mass of 60 GeV/c{sup 2}. This achieves the best sensitivity for dark matter WIMPs with masses above 44 GeV/c{sup 2}, and significantly restricts the parameter space for some favored supersymmetric models.
We report results of a search for weakly interacting massive particles (WIMPs) with the Si detectors of the CDMS II experiment. This report describes a blind analysis of the first data taken with ...CDMS II's full complement of detectors in 2006-2007; results from this exposure using the Ge detectors have already been presented. We observed no candidate WIMP-scattering events in an exposure of 55.9 kg-days before analysis cuts, with an expected background of ~ 1.1 events. The exposure of this analysis is equivalent to 10.3 kg-days over a recoil energy range of 7-100 keV for an ideal Si detector and a WIMP mass of 10 GeV /c super(2). These data set an upper limit of 1.7 X 10 super(-41) cm super(2) on the WIMP-nucleon spin-independent cross section of a 10 GeV /c super(2) WIMP. These data exclude parameter space for spin-independent WIMP-nucleon elastic scattering that is relevant to recent searches for low-mass WIMPs.
PDF
