Construction of the LUX Dark Matter Experiment at the Sanford Underground Science and Engineering Laboratory

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PROPOSAL NUMBER: 0750671INSTITUTION: Case Western ReserveNSF PROGRAM: PHY ? UNDERGROUND PHYSICSPRINCIPAL INVESTIGATOR: Shutt, Thomas A.TITLE: Construction of the LUX Dark Matter Experiment at the Sanford Underground Science and Engineering Laboratory ABSTRACTA wealth of observations, dating back 70 years, show that the universe is composed of 96% invisible matter and energy. The nature of these missing components is one of the most fundamental mysteries in physics. The leading candidate for the invisible ?dark matter? is a subatomic particle left over from the big bang known as the Weakly Interacting Massive Particle (WIMP). Such particles are also predicted by supersymmetry, a favored class of new particle models. Although they only very rarely interact with conventional matter, they should be detectable by sufficiently sensitive detectors on Earth, through their direct interaction with, and the ensuing recoil of, nuclei in a target material. The primary challenge in detecting them is reducing natural and cosmogenic radioactivity by up to 10 orders of magnitude.The Large Underground Xenon (LUX) collaboration has assembled a team with the breadth and depth of experience to construct and deploy a large two-phase liquid xenon dark matter detector and water shield, to be installed at a deep underground laboratory (Homestake). LUX is composed of groups that bring essential experience in background rejection and rare event detection.This award will provide funds to design, construct and deploy a 300 kg active mass two-phase Xe experiment that will extend current dark matter sensitivity two orders of magnitude beyond current best limits, to an event rate better than ~1 event/100 kg/month. A large detector is required to not only set such a sensitivity limit, but also to accumulate WIMP statistics in a reasonable time if a signal is detected. The LUX program will also help develop the technologies required for 1?10 ton dark matter detectors.Among the Broader Impacts of this research: the detection of particle dark matter would transform and extend world activities in the particle physics and astronomical communities. Moreover, the techniques themselves can be further scaled up and applied to other fundamental experiments such as double beta decay and solar neutrinos. As with other particle detection techniques, new methods of position sensitivity and particle discrimination may give rise to new medical diagnostic techniques, or applications to Homeland Security and nuclear control.