Japan’s “T2K,” one of our favorite neutrino experiments (we’re keen on several), might have just cracked the mystery of why matter triumphed over antimatter after the Big Bang (they should have canceled each other out). The international experiment’s data from earlier this year--before its science was interrupted by the earthquake in March--indicates that muon neutrinos can transform into electron neutrinos.
A primer on neutrinos and why we should care about them: Neutrinos are one of the fundamental building blocks of matter, though they interact very weakly with normal matter (innumerable neutrinos kicked out by the sun pass straight through the earth at any moment, rarely pausing to interact with the planet). They come in three flavors: muon neutrinos, electron neutrinos, and and tau neutrinos. And for the aforementioned reason they are very hard to detect.Nonetheless, via detectors like T2K (for Tokai-to-Kamioka, as these are the origin and terminus of the nearly 200-mile experiment) we are able to detect and study neutrinos every now and again. T2K fires a beam of muon neutrinos straight through the ground from Tokai on the east coast to the Super-Kamiokande detector 183 miles away. And recently at Super-K, some of the neutrinos detected were electron neutrinos, indicating that they has had shifted mid-flight.