Scientists get closer to understanding dark matter

A single unexplained interaction deep underground has given dark-matter researchers one of their most intriguing clues yet, although they stress that it is not a discovery.

The event came from the LUX-ZEPLIN experiment, known as LZ, nearly a mile below ground at the Sanford Underground Research Facility in South Dakota. The experiment uses about 10 tonnes of ultrapure liquid xenon to search for weakly interacting massive particles, or WIMPs, one of the leading theoretical candidates for dark matter.

Researchers said the interaction has proved difficult to explain through known background processes. After accounting for the “look-elsewhere” effect, the LZ collaboration calculated a global statistical significance of 2.6 sigma. That remains well below the level required to claim a discovery.

Dark matter cannot be seen directly. Scientists infer its presence from the gravitational influence it exerts on galaxies and other cosmic structures, and estimate that it accounts for about 85% of the universe’s matter.

The researchers will continue collecting data. Further observations could strengthen the signal or show that it disappears.