An experiment searching for cosmic dark matter may have finally detected something. But it’s not dark matter.
Scientists with the XENON1T experiment reported data June 17 showing an unexpectedly large number of blips within their detector. “We observe an excess … and we don’t know what it is,” said physicist Evan Shockley of the University of Chicago, who described the result during a virtual seminar.
The blips could be explained by weird new particles called solar axions, or unexpected magnetic properties for certain known particles, neutrinos, the researchers propose.
Or the excess might instead be the result of a more banal scenario: A tiny amount of radioactive tritium could have found its way into the detector. None of the possibilities would explain the nature of dark matter, an unseen substance in the universe that helps stars cling to their galaxies and explains how structures formed in the early universe.