Dark matter is thought to account for the majority of the mass in the universe, yet it neither emits nor reflects light.
Because it is invisible, physicists can only infer its presence from its gravitational pull on stars and galaxies.
To catch it in the act, researchers built the LUX-ZEPLIN experiment far below the Earth's surface, shielded from interference.
Recently the detector registered a rare particle interaction that resists easy explanation as ordinary background noise.
Tantalisingly, the event turned up precisely in the range where a dark matter signal might be expected.
Despite the excitement, the collaboration is deliberately restrained in its claims.
A single unusual event is not enough, and the team insists that far more data is required.
Only repeated, consistent signals could justify announcing an actual detection.