Scientists searching for dark matter spot a signal that defies explanation

An international team of scientists says it has detected an intriguing signal that could hint at evidence of dark matter, offering a clue that might bring the mystery of the elusive substance one step closer to a solution. Dark matter makes up about 85% of all the matter in the universe and is about five times as abundant as ordinary matter, which makes up stars, planets and everything else that scientists can see. Dark matter is invisible because it does not absorb or reflect light, but it does interact with regular matter, and its gravitational effects are needed to explain the structure of the universe. NASA’s Hubble telescope detects possible ‘dark galaxy’ For nearly half a century — since American astronomers Vera Rubin and W. Kent Ford provided some of the strongest evidence for dark matter’s existence — scientists have tried to identify the unseen substance, more recently using sophisticated devices designed to detect potential candidates. One of these devices is the LUX-ZEPLIN, or LZ, experiment — a detector containing 7 active metric tons of liquid xenon that’s in a former gold mine nearly a mile (about 1.5 kilometers) below Earth’s surface at the Sanford Underground Research Facility in South Dakota. The detector registered an unusual particle interaction in June 2023 that generated a flash of light and cautious excitement. The LZ collaboration is an international group of 250 scientists and engineers from 39 institutions. After months of analysis, the team estimates only a 0.5% chance that a known source of interference caused the event — making this signal the most compelling hint of dark matter the instrument has ever recorded. However, in scientific terms, claiming a discovery requires a much higher degree of confidence. “One event, by itself, is not enough,” Alvine Kamaha, an assistant professor of physics at the University of California, Los Angeles, said in an email. “We need to see whether additional events appear as we collect more data and whether the statistical significance of the observation increases,” said Kamaha, a member of the LZ collaboration who helped build the LZ detector. Sam Eriksen, a senior research associate of physics at the University of Bristol and member of the LZ collaboration, presented the findings September 1 at the TeV Particle Astrophysics 2026 conference in Japan, and the team has submitted a study for publication in the scientific journal Physical Review Letters. The researchers are already working on further analysis that could potentially increase the statistical significance of the event. The threshold to claim a discovery in particle physics is known as 5-sigma, which means about a 1 in 3.5 million chance of a statistical fluke rather than a real hint of dark matter. The analysis is currently at 2.6-sigma, or a 1 in 200 chance of a fluke. A definitive detection of dark matter would be “a major breakthrough,” Kamaha said. “We know that dark matter plays a fundamental role in the formation of galaxies and the large-scale structure of the universe, but we still do not know what it actually is,” she said. “It’s exciting because it would open an entirely new area of particle physics.” There are several candidates for what dark matter could be, including primordial black holes or an undiscovered particle. Detectors such as the LZ experiment search for a class of hypothetical particles called weakly interacting massive particles, or WIMPs. [Read Full Story on CNN →](https://www.cnn.com/2026/09/14/science/dark-matter-lz-experiment-potential-signal)