Deep beneath the Apennines, China’s Jinping Mountains and a mine in South Dakota, large detectors filled with liquid xenon are searching for dark matter. The underground sites help shield the instruments from other signals as researchers look for evidence of weakly interacting massive particles, or WIMPs.
The expected signal would occur if a WIMP collided with a xenon atom, producing a flash of light and an electrical charge. Detectors have begun recording occasional signals, but these have been attributed to neutrinos rather than dark matter. Produced in vast quantities by stars, neutrinos are lightweight subatomic particles that can pass through Earth, making them difficult to block.
Physicists have long known that neutrinos would create background noise. They had hoped to detect WIMPs first, but the size and sensitivity of current detectors may mean that neutrino signals drown out other events. The article suggests that the next experiment using this approach could be the last of its kind.
That would not end the search for dark matter. Kathryn Zurek, a theoretical particle physicist at the California Institute of Technology, says researchers are broadening their efforts. No new particles have been found at the Large Hadron Collider, and WIMP dark matter has yet to be detected, but Zurek notes that many other possible candidates remain to be investigated.
Sources: t3n.