Researchers re-calibrate world's most sensitive dark matter detector

LEAD, S.D., Dec. 14 (UPI) -- The Large Underground Xenon is science's best hope for confirming the existence of dark matter.

The world's most sensitive dark matter detector is located a mile beneath the Black Hills of South Dakota at the Sanford Underground Research Facility, or SURF.

According to the results of recent testing -- shared in the journal Physical Review Letters -- the detector is now more sensitive than ever.

"We have improved the sensitivity of LUX by more than a factor of 20 for low-mass dark matter particles, significantly enhancing our ability to look for WIMPs," Rick Gaitskell, professor of physics at Brown University, said in a press release. "It is vital that we continue to push the capabilities of our detector in the search for the elusive dark matter particles."

The LUX detector is giant tank of liquid xenon surrounded by ultra-sensitive photon detectors. The device is designed to measure weakly interacting massive particles, or WIMPs, a leading dark matter candidate.

Scientists theorize that when a dark matter particle, or WIMP, collides with a xenon atom, its nucelus will recoil and put out a tiny flash of light.

It's thought that these dark matter particles may have fallen out of thermal equilibrium from the dense, hot plasma of the early universe. If these escaped particles persist, as theorized, researchers hope the LUX detector can find them.

"We look for WIMPs produced in the Big Bang that are still around, up to very high masses -- we have the best sensitivity of any experiment to date for WIMP masses above four times that of a proton," explained Daniel McKinsey, a LUX researcher and a professor of physics at the University of California, Berkeley, said in a press release. "We haven't yet observed dark matter interactions, but the search goes on."

The new sensitivity was made possible by a re-calibration of the device's detectors, which rule out bogus interactions and collisions among cosmic and gamma rays. By ruling out conflicting collisions, researchers can better hone LUX to search out possible dark matter interactions.

"These calibrations have deepened our understanding of the response of xenon to dark matter, and to backgrounds," added Alastair Currie, researcher with LUX and Imperial College London. "This allows us to search, with improved confidence, for particles that we hadn't previously known would be visible to LUX."

LUX only has a few more months to make good on its improved sensitivity. In late 2016, LUX will be retired to make way for a new, larger and more powerful detector called the LUX-ZEPLIN, or LZ, experiment.