Dark Matter Experiment Most Sensitive Yet, Researchers Report

The Large Underground Xenon (LUX) is the most powerful tool ever developed in the hunt for dark matter, according to the experiment's first job report.

Incapable of emitting or reflecting light, dark matter has never been detected directly. Still, scientists say that without it and its gravitational influence, galaxies and galaxy clusters would simply fly apart.

"To give some idea of how small the probability of having a dark matter particle interact, imagine firing one dark matter particle into a block of lead," Rick Gaitskell, professor of physics at Brown University and co-spokesperson for LUK, said in a statement. "In order to get a 50-50 chance of the particle interacting with the lead, the block would need to stretch for about 200 light years -- this is 50 times farther than the nearest star to the Earth aside from the sun. So it's an incredibly rare interaction."

The LUX is a third of a ton of supercooled xenon in a tank equipped with light sensors capable of detecting a single photon at a time. Whenever a particle interacts with the xenon, a flash and ion charge are created. In order to hide the entire contraption away from as much interference as possible, researchers buried the LUX nearly 5,000 feet underground and within more than 70,000 gallons of deionized water.

The results, Gaitskell explains, is a "supremely quiet" realm in which researchers are able to carry out some of the most precise dark matter experiments ever.

"LUX is a huge step forward. Within the first few minutes of switching it on, we surpassed the sensitivity of the first dark matter detectors I was involved with 25 years ago," he said. "Within a few days, it surpassed the sensitivity of sum total of all previous dark matter direct search experiments I have ever worked on."

The first 90-day run has focused on the quality of the detector's performance, with researchers hoping that in the upcoming 300-day run they will be able to either definitively detect dark matter or drastically narrow the search.

"Every day that we run a detector like this we are probing new models of dark matter," Gaitskell said. "That is extremely important because we don't yet understand the universe well enough to know which of the models is actually the correct one. LUX is helping to pin that down."