An international team of researchers has detected a single unexplained particle interaction deep underground that resembles the signature of a hypothetical dark matter particle, though they stressed it is not yet confirmed as a discovery.
The event was recorded by the LUX-ZEPLIN (LZ) experiment, which uses a large tank of ultra-pure liquid xenon surrounded by hundreds of light sensors at the Sanford Underground Research Facility in an old gold mine in South Dakota’s Black Hills.
After analysing 220 days of data collected between March 2023 and April 2024, the team of about 250 scientists and engineers from 38 institutions identified the interaction on June 16, 2023. It matched the expected two flashes of light that would occur if a weakly interacting massive particle, or WIMP, struck a xenon nucleus.
Sam Ericks, the study’s lead and a senior research associate at the University of Bristol, presented the findings at the 2026 TeV Particle Astrophysics conference in Japan. “We understand our detectors and background so well that even a single unusual event like the one we found is very significant,” he said in a press release.
Rick Gaitskell, LZ spokesperson and a physicist at Brown University, cautioned against overstating the result. “We are not claiming to have seen dark matter,” he said.
Physicists describe the signal as the most credible one produced by LZ so far. Theresa Fruth, a University of Sydney physicist involved in the work, told ABC News the finding remained consistent after repeated checks. “This event has not disappeared even after many checks,” she said.
Dark matter is thought to make up about 27 percent of the universe’s mass-energy content. It does not emit or reflect light and has been inferred only through its gravitational effects on galaxies and light. Ordinary matter accounts for just five percent of the cosmos.
Researchers continue to analyse the data and plan further observations to determine whether the interaction points to a new particle beyond the Standard Model of physics.
