Fiat LUX: Dark-matter detector’s initial results

The nature of the dark matter that makes up some 85% of the material stuff of the universe remains a mystery. Current consensus favors a weakly interacting massive particle, or WIMP, inspired by extensions of the standard model of particle physics. One approach to understanding those putative particles is to look for their rare interactions with conventional matter. A number of experiments have undertaken such searches. Last week the most sensitive of them, the LUX (Large Underground Xenon) experiment, announced via webcast its first results. The experiment’s initial three-month run saw no evidence of WIMPs, which significantly lowered the upper limits for the mass-dependent WIMP interaction strength. Moreover, the new results ruled out the handful of possible light-WIMP sightings that had been reported earlier. Located 1.5 km belowground at the Sanford Underground Research Facility in Lead, South Dakota, the LUX detector monitors 250 kg of liquid xenon. When a WIMP...