Status of the LUX Dark Matter Search

The Large Underground Xenon (LUX) dark matter search experiment is currently being deployed at the Homestake Laboratory in South Dakota. We will highlight the main elements of design which make the experiment a very strong competitor in the field of direct detection, as well as an easily scalable concept. We will also present its potential reach for supersymmetric dark matter detection, within various timeframes ranging from 1 year to 5 years or more.Comment: 4 pages, in proceedings of the SUSY09 conferenc

Probing the Local Velocity Distribution of WIMP Dark Matter with Directional Detectors

We explore the ability of directional nuclear-recoil detectors to constrain the local velocity distribution of weakly interacting massive particle (WIMP) dark matter by performing Bayesian parameter estimation on simulated recoil-event data sets. We discuss in detail how directional information, when combined with measurements of the recoil-energy spectrum, helps break degeneracies in the velocity-distribution parameters. We also consider the possibility that velocity structures such as cold tidal streams or a dark disk may also be present in addition to the Galactic halo. Assuming a carbon-tetrafluoride detector with a 30-kg-yr exposure, a 50-GeV WIMP mass, and a WIMP-nucleon spin-dependent cross-section of 0.001 pb, we show that the properties of a cold tidal stream may be well constrained. However, measurement of the parameters of a dark-disk component with a low lag speed of ~50 km/s may be challenging unless energy thresholds are improved.Comment: 38 pages, 15 figure

Radiogenic and Muon-Induced Backgrounds in the LUX Dark Matter Detector

The Large Underground Xenon (LUX) dark matter experiment aims to detect rare low-energy interactions from Weakly Interacting Massive Particles (WIMPs). The radiogenic backgrounds in the LUX detector have been measured and compared with Monte Carlo simulation. Measurements of LUX high-energy data have provided direct constraints on all background sources contributing to the background model. The expected background rate from the background model for the 85.3 day WIMP search run is $(2.6\pm0.2_{\textrm{stat}}\pm0.4_{\textrm{sys}})\times10^{-3}$~events~keV$_{ee}^{-1}$~kg$^{-1}$~day$^{-1}$ in a 118~kg fiducial volume. The observed background rate is $(3.6\pm0.4_{\textrm{stat}})\times10^{-3}$~events~keV$_{ee}^{-1}$~kg$^{-1}$~day$^{-1}$, consistent with model projections. The expectation for the radiogenic background in a subsequent one-year run is presented.Comment: 18 pages, 12 figures / 17 images, submitted to Astropart. Phy

After LUX: The LZ Program

The LZ program consists of two stages of direct dark matter searches using liquid Xe detectors. The first stage will be a 1.5-3 tonne detector, while the last stage will be a 20 tonne detector. Both devices will benefit tremendously from research and development performed for the LUX experiment, a 350 kg liquid Xe dark matter detector currently operating at the Sanford Underground Laboratory. In particular, the technology used for cryogenics and electrical feedthroughs, circulation and purification, low-background materials and shielding techniques, electronics, calibrations, and automated control and recovery systems are all directly scalable from LUX to the LZ detectors. Extensive searches for potential background sources have been performed, with an emphasis on previously undiscovered background sources that may have a significant impact on tonne-scale detectors. The LZ detectors will probe spin-independent interaction cross sections as low as 5E-49 cm2 for 100 GeV WIMPs, which represents the ultimate limit for dark matter detection with liquid xenon technology.Comment: Conference proceedings from APS DPF 2011. 9 pages, 6 figure