Theory said that a muon neutrino could almost instantly change into an electron neutrino.

理论上，μ中微子几乎能秒变称电子中微子。

At an experiment in Japan called T2K, a particle accelerator fires a beam of muon neutrinos at a giant detector on the opposite coast, some 185 miles away.

日本做的一项叫“T2K”的实验中，一台粒子加速器向对岸的一台大型探测器发射了一束μ中微子。