Researchers in Japan find that neutrinos can flip to any of their three flavors

BBC : Researchers at Japan’s multinational T2K project say they have seen indications that neutrinos—electrically neutral elementary particles—can spontaneously change into any of their types, or flavors: electron neutrinos, muon neutrinos, or tau neutrinos, writes Jonathan Amos for the BBC. The T2K project involves two facilities: The Japan Proton Accelerator Research Complex (J-PARC), on the country’s east coast, generates a beam of muon neutrinos that it fires under the ground for 295 km to the Super-Kamiokande facility on the west coast. In experiments run this year on T2K, researchers found that an excess of electron neutrinos turned up at Super-K. They believe the muon neutrinos sent from J-PARC changed flavor in flight. The data could indicate that the oscillations of neutrinos and their antiparticles (antineutrinos) could be different—an example of CP violation and a potential explanation for why normal matter and antimatter created at the Big Bang did not annihilate each other but left instead an excess of normal matter. Although the statistics are not big enough to claim a discovery, the T2K collaboration is excited. Experiments had to be suspended in the wake of the Tohoku earthquake in March, but the facility should be up and running again by the end of the year.