D. S. Akerib

We report constraints on spin-independent weakly interacting massive particle (WIMP)-nucleon scattering using a 3.35×10^{4} kg day exposure of the Large Underground Xenon (LUX) experiment. A dual-phase xenon time projection chamber with 250 kg of active mass is operated at the Sanford Underground Research Facility under Lead, South Dakota (USA). With roughly fourfold improvement in sensitivity for high WIMP masses relative to our previous results, this search yields no evidence of WIMP nuclear recoils. At a WIMP mass of 50 GeV c^{-2}, WIMP-nucleon spin-independent cross sections above 2.2×10^{-46} cm^{2} are excluded at the 90% confidence level. When combined with the previously reported LUX exposure, this exclusion strengthens to 1.1×10^{-46} cm^{2} at 50 GeV c^{-2}.

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.

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 $6.6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}44}\text{ }\text{ }{\mathrm{cm}}^{2}$ ($4.6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}44}\text{ }\text{ }{\mathrm{cm}}^{2}$ when combined with previous CDMS II data) at the 90% confidence level for a WIMP mass of $60\text{ }\text{ }\mathrm{GeV}/{c}^{2}$. This achieves the best sensitivity for dark matter WIMPs with masses above $44\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, and significantly restricts the parameter space for some favored supersymmetric models.

We have observed the decays ${\mathit{B}}^{0}$\ensuremath{\rightarrow}${\mathit{K}}^{\mathrm{*}}$(892${)}^{0}$\ensuremath{\gamma} and ${\mathit{B}}^{\mathrm{\ensuremath{-}}}$\ensuremath{\rightarrow}${\mathit{K}}^{\mathrm{*}}$(892${)}^{\mathrm{\ensuremath{-}}}$\ensuremath{\gamma}, which are evidence for the quark-level process b\ensuremath{\rightarrow}s\ensuremath{\gamma}. The average branching fraction is (4.5\ifmmode\pm\else\textpm\fi{}1.5\ifmmode\pm\else\textpm\fi{}0.9)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}5}$. This value is consistent with standard model predictions from electromagnetic penguin diagrams.