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 .

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We present constraints on weakly interacting massive particles (WIMP)-nucleus scattering from the 2013 data of the Large Underground Xenon dark matter experiment, including 1.4 × 10 4 kg day of search exposure. This new analysis incorporates several advances: single-photon calibration at the scintillation wavelength, improved event-reconstruction algorithms, a revised background model including events originating on the detector walls in an enlarged fiducial volume, and new calibrations from decays of an injected tritium β source and from kinematically constrained nuclear recoils down to 1.1 keV. Sensitivity, especially to low-mass WIMPs, is enhanced compared to our previous results which modeled the signal only above a 3 keV minimum energy. Under standard dark matter halo assumptions and in the mass range above 4 GeV c −2 , these new results give the arXiv:1512.03506v3 [astro-ph.CO]

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/c2. This analysis provides stronger constraints than previous CDMS II results for WIMP masses below 9 GeV/c2 and excludes parameter space associated with possible low-mass WIMP signals from the DAMA/LIBRA and CoGeNT experiments.

LUX-ZEPLIN (LZ) is a next-generation dark matter direct detection experiment that will operate 4850 feet underground at the Sanford Underground Research Facility (SURF) in Lead, South Dakota, USA. Using a two-phase xenon detector with an active mass of 7 tonnes, LZ will search primarily for low-energy interactions with weakly interacting massive particles (WIMPs), which are hypothesized to make up the dark matter in our galactic halo. In this paper, the projected WIMP sensitivity of LZ is presented based on the latest background estimates and simulations of the detector. For a 1000 live day run using a 5.6-tonne fiducial mass, LZ is projected to exclude at 90% confidence level spin-independent WIMP-nucleon cross sections above 1.4 × 10 −48 cm 2 for a 40 GeV=c 2 mass WIMP. Additionally, a 5σ discovery potential is projected, reaching cross sections below the exclusion limits of recent experiments. For spin-dependent WIMP-neutron(-proton) scattering, a sensitivity of 2.3 × 10 −43 cm 2 (7.1 × 10 −42 cm 2) for a 40 GeV=c 2 mass WIMP is expected. With underground installation well underway, LZ is on track for commissioning at SURF in 2020.

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We report on the first axion search results from the Cryogenic Dark Matter Search (CDMS) experiment at the Soudan Underground Laboratory. An energy threshold of 2 keV for electron-recoil events allows a search for possible solar axion conversion into photons or local galactic axion conversion into electrons in the germanium crystal detectors. The solar axion search sets an upper limit on the Primakov coupling g(agammagamma) of 2.4x10(-9) GeV-1 at the 95% confidence level for an axion mass less than 0.1 keV/c2. This limit benefits from the first precise measurement of the absolute crystal plane orientations in this type of experiment. The galactic axion search analysis sets a world-leading experimental upper limit on the axioelectric coupling g(aee) of 1.4x10(-12) at the 90% confidence level for an axion mass of 2.5 keV/c2.

We present measurements of the electron-recoil (ER) response of the LUX dark matter detector based upon 170,000 highly pure and spatially-uniform tritium decays. We reconstruct the tritium energy spectrum using the combined energy model and find good agreement with expectations. We report the average charge and light yields of ER events in liquid xenon at 180 V/cm and 105 V/cm and compare the results to the NEST model. We also measure the mean charge recombination fraction and its fluctuations, and we investigate the location and width of the LUX ER band. These results provide input to a re-analysis of the LUX Run3 WIMP search .