Dark matter accounts for most of the matter in the universe, and yet we know very little about it. Scientists around the world are inching closer and closer to a discovery, and although we are yet to directly observe it, we are shrinking the pool of possible masses these particles can have.
The Large Underground Xenon (LUX) dark matter experiment is the most sophisticated dark matter detector in the world, and now a new set of calibrations has dramatically improved its sensitivity. LUX is looking for weakly interactive massive particles (WIMPs), particles which have many times the mass of a proton but hardly interact with other matter.
“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,” said Rick Gaitskell, professor of physics at Brown University and co-spokesperson for the LUX experiment, in a statement.
“It is vital that we continue to push the capabilities of our detector in the search for the elusive dark matter particles.”
The new research is described in a paper submitted to Physical Review Letters and available on ArXiv. The team has re-examined the data collected during the first 95-day search in 2013 and was able to rule out low-mass WIMPs previously reported to be detected.
The detector consists of a tank filled with 370 kilograms (815 pounds) of xenon surrounded by 61 photomultiplier tubes. On very rare occasions a WIMP hits a xenon atom, and as the atom recoils it emits a flash of light which is detected by the tubes.
LUX has not detected a single WIMP yet, but its unmatched sensitivity allowed the team to rule out vast mass ranges that WIMPs might have. The detector is the best there is at non-detections of dark matter, as weird as that may sound.
The latest run began in 2014 and is expected to continue until June 2016. This run will be more than four times longer than the previous one. And the team is hoping for an actual detection of dark matter time around.