Sometimes, finding nothing is just as good as finding something. Physicists have made the most sensitive measurements yet in the hunt for a rare event that could undermine the dominant theory of particle physics, and turned up zilch.

The scientists, who are searching for a rumored particle decay process called “neutrinoless double-beta decay,” ran a finely tuned detector for almost seven months, and found no significant data to suggest the process occurs. That non-detection hints that exotic particles called neutrinos may be more mundane than some have thought.