The neutrino is one of the least understood particles. One of the biggest open questions is whether it is its own antiparticle. If it is, it would help explain why there is more matter in the universe than antimatter. Scientists working a joint Italian-U.S. experiment released new results on a search for an extremely rare event that can only occur if neutrinos are their own antiparticles. After two months of very detailed research, they didn’t observe the event.