Pontecorvo predicts neutrino flavor oscillations
Today, the idea of neutrino oscillations is indispensable to the field of neutrino physics. But in 1957, when it was first suggested by Italian physicist Bruno Pontecorvo, it was a wild notion. He thought that there was an analogy between leptons and hadrons and that neutrinos could oscillate in an analogous way to neutral kaon mixing. But, in order to oscillate, neutrinos must have mass; whether they did was unknown at the time. In addition, oscillation today means to change from one type of neutrino to another, but in 1957, there was only one known type, now called “flavor,” of neutrino.
Neutrino oscillations would be first observed experimentally 40 years later, after Pontecorvo’s death. But his idea of neutrino masses, mixing, and oscillations established a new field of neutrino research and changed neutrino physics forever. Read more here.