Researchers searching for dark matter have detected unexpected signals through two distinct methods, capturing an unusual particle interaction deep underground in South Dakota and analyzing a decade of geomagnetic data that suggests Earth itself can act as a natural detector for elusive ultralight particles.
The LUX-ZEPLIN Experiment Records a Rare Underground Interaction
Scientists hunting for the substance believed to make up roughly 85 percent of all matter in the universe have recorded an unusually compelling event inside the LUX-ZEPLIN detector, which sits nearly a mile underground at the Sanford Underground Research Facility in South Dakota. The detector brings together 250 scientists and engineers across 39 institutions and is managed by the U.S. Department of Energy’s Lawrence Berkeley National Laboratory.
At the core of the experiment are 10 tonnes of extremely pure liquid xenon enclosed in a cylindrical time projection chamber. The research team examined 220 live days of data gathered between March 2023 and April 2024, broadening their search beyond simpler weakly interacting massive particle interactions to release greater amounts of energy.
The analysis revealed a single particle interaction that resists straightforward explanation through ordinary background matter. Researchers presented these findings during a scientific talk at the 2026 TeV Particle Astrophysics conference in Japan.
We’re very intrigued to see this event in the data, in the region where we expect dark matter to show up and the competing backgrounds are very low.
Rick Gaitskell, professor at Brown University and spokesperson for LZ
While the observation offers the strongest dark matter hint the LUX-ZEPLIN experiment has reported so far, it stops short of definitive proof.
Turning Planet Earth Into a Giant Resonator for Axions
While underground detectors watch for heavy particles, a separate international team pursued a vastly larger scale by treating Earth itself as a giant detector. Researchers from Kyoto University, Hiroshima University, and Nihon University focused on ultralight candidates like axions and dark photons, which are roughly 19 to 21 orders of magnitude lighter than an electron.
Because traditional laboratory magnets cover only small areas, theoretical physicist Atsushi Taruya and colleagues investigated whether the planet’s natural electromagnetic environment could amplify signals from these elusive candidates. The region between Earth’s surface and the ionosphere acts as a natural cavity resonator for electromagnetic waves.
We asked ourselves whether we could use the Earth itself as a giant detector in the search.
Atsushi Taruya, theoretical physicist
To probe frequencies above 1 Hz, the team developed a novel theoretical framework that accounts for atmospheric electrical conductivity. Their model predicted that the Earth-ionosphere cavity would amplify signals near 8 Hz, yielding reliable predictions up to roughly 30 Hz.
Analyzing a Decade of Geomagnetic Measurements
To test the new framework, the researchers turned to 10 years of geomagnetic measurements gathered between 2012 and 2022 by the British Geological Survey’s Eskdalemuir Observatory. After removing artificial noise sources, the worldwide hunt for dark matter yielded numerous candidate signals.
The theoretical models indicate distinct geographic patterns for these candidates. Axion signals depend on Earth’s magnetic field and should vary by location, appearing strongest in Southeast Asia and weakening near the poles. Dark photon signals, by contrast, would emerge uniformly across the planet regardless of magnetic strength. Because the observatory data came entirely from a single site in the UK, verifying these global distinctions requires broader geographic data collection.
Gravitational Waves and the Search for Dense Signatures
In a parallel effort published in Physical Review Letters, researchers analyzed signals from gravitational wave detectors to spot the indirect imprint of invisible matter. Astronomers modeled how gravitational waves should appear if they emerged from black holes moving through dense dark matter rather than empty space, then applied that model to real data from the LIGO-Virgo-KAGRA network.
However, one specific event designated as GW190728 displayed features consistent with the imprint of dark matter.
We know that dark matter is around us. It just has to be dense enough for us to see its effects.
Josu Aurrekoetxea, MIT Department of Physics
While these varied techniques—from underground xenon chambers and planetary-scale resonance to gravitational wave analysis—have yet to yield a confirmed discovery, they provide tighter experimental limits and fresh pathways for exploring the most elusive components of the universe.