The LUX (large underground xenon) detector, using almost 800 lb of liquid xenon and being installed in the former Homestake gold mine in South Dakota, is the latest of several attempts to discover so-called "dark matter"--hypothesized to make up about a quarter of the universe's mass-energy, which cannot be associated with known and measured sources. New England has strong representation in the effort, led by principal investigators Profs. Richard Gaitskell at Brown, Masahiro Morii at Harvard, Thomas Shutt at Case Western, Adam Bernstein at Lawrence Livermore and Isabel Lopes at Universidade de Coimbra, Portugal. [ Amber Hunt, Associated Press, Dark-matter detector has new home in South Dakota, Boston Globe, July 13, 2012, at ]

For environmental protection and job generation, South Dakota committed about $40 million to pump out water from the mine, almost a mile deep. NSF and the U.S Department of Energy committed matching funds totaling $170 million, much of that from 2009 "stimulus" funds. Philanthropist T. Denny Sanford donated about $70 million to build an underground laboratory. The LUX experiment is the first to use the facility. LUX has been getting DoE funding, miniscule by standards of high-energy physics: about $1.5 million to build the detector and about $2 million/year to sustain operations. So far, the effort has been underway for about eight years and funded for about six years. A potential follow-on effort is currently in suspense.

The most popular candidates for "dark matter" are so-called "weakly interacting massive particles" (WIMPs), a topic of scientific speculation for over 20 years. So far, searching for WIMPs has enjoyed somewhat more respectability but no more success than the late 1960s searches for "tachyons" and the late 1980s searches for "cold fusion."

After several earlier failures to get positive results, the LUX experiment will push the estimated threshold cross-section for WIMP interactions below 1 zeptobarn/nucleon in the WIMP mass range 20-200 Gev, for three years of operation--comparable to the range of sensitivity that was needed to discover the Higgs boson. However, a consensus of opinion appears to be that larger detectors with more sensitivity will be needed, if indeed WIMPs do exist and do interact as hypothesized. [ Mani Tripathi, Large underground xenon experiment, UC Davis, 2007, at ]