LUX Operations at the Sanford Underground Research Facility

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Observations indicate that 80% of the matter in the Universe is not made of normal atoms, but must be otherwise undetected elementary "dark matter" particles that do not emit or absorb light. Remarkably, particle physics theories proposed for other reasons predict the existence of Weakly Interacting Massive Particles (WIMPs) with just the right properties to be this dark matter. If WIMPs are the dark matter, they may be detectable when they scatter in Earth-based detectors. Direct detection of WIMP dark matter would solve a fundamental mystery in particle physics and cosmology, providing a unique window to learning about the primary matter constituent of the Universe and of physics beyond the Standard Model of particle physics. The Large Underground Xenon experiment (LUX) is a two-phase (liquid/gas) xenon (LXe) experiment designed for the search for dark matter interactions with ordinary matter.Development of technology related to LXe will find use in the increasing number of experiments worldwide using noble liquids as detection materials. These projects will also result in technical training in radiation detection, cryogenics, and gas purification for graduate and undergraduate students. LXe has practical applications to gamma ray imaging for astrophysics, Homeland Security, and medical imaging. There are frequent tours of the facility and presentations on the underground experiments for the region's schools and college classes, and they maintain strong outreach efforts to the region's American Indian Colleges and Tribal Councils.Located in the Sanford Underground Research Facility (SURF) in Lead, South Dakota, LUX has a fiducial mass of about 100 kg and promises substantially improved sensitivity to the WIMP model. From its operations to date, LUX has the most sensitive limit in the world for spin-independent dark matter interactions for WIMP masses above 6 GeV. This award provides support for continued LUX operations, followed by decommissioning, over the period of March 2015 through December 2016. Continued LUX operation through mid-2016 is expected to result in considerably improved sensitivity, reaching a factor of five in improvement over existing limits at high WIMP masses.