New LUX experiment: no dark matter in this corner

The LUX detector.

Lawrence Berkeley Lab

Dark matter is perhaps the most frustrating substance we know. Invisible to all forms of light, we detect its presence through its gravitational influence alone. That's insufficient, though: physicists and astronomers alike would like to know what it is. Yet so far, we're better able to say what it isn't: it's not the stuff of normal matter (electrons, quarks) or other particles we know about, like neutrinos.

The process of figuring out what dark matter isn't received a major push today with the announcement of the first three months of data from the Large Underground Xenon (LUX) detector. Unfortunately, LUX failed to find any dark matter, ruling out some possible detections by other experiments.

Experiments attempting to detect dark matter focus mainly on one possible class, motivated by particle physics: WIMPs, or weakly interacting massive particles. The "weak" part of the name originally referred to the weak force, one of the four known fundamental forces in nature. However, WIMPs may or may not actually interact via the weak force—we know for certain dark matter interacts gravitationally, but whether it interacts with ordinary matter via any other force is currently unknown.