Question: In particle physics, a massless particle is an elementary particle whose invariant mass is zero, the discovery of this phenomenon, known as neutrino oscillation, led to which Japanese physicist, known for neutrino experiments at the Kamiokande and its successor, Super-Kamiokande, shared the 2015 Nobel prize in physics?
Sentence (from "Kamioka Observatory"): A set of groundbreaking neutrino experiments have taken place at the observatory over the past two decades.
Relevant evidence: No