Except in horror movies, most scientific experiments don’t start with scientists snooping around narrow, deserted hallways. But a tucked-away location in the recesses of the Department of Energy’s (DOE) Oak Ridge National Laboratory (ORNL) provided exactly what Yuri Efremenko was looking for. Efremenko, an ORNL researcher and University of Tennessee

The MINERvA collaboration analyzed data from the interactions of an antineutrino—the antimatter partner of a neutrino—with a nucleus. They were surprised to find evidence that antineutrinos interacted with pairs of particles inside the nucleus. They had expected antineutrinos to interact with just single protons or neutrons. To see this evidence,