Hyper-Kamiokande — A Next Generation Water Cherenkov Detector

A next generation water Cherenkov detector at Kamioka with a total mass of ~1 Mton is called Hyper-Kamiokande. If the beam intensity of a 50-GeV proton synchrotron now under construction at Tokai is upgraded to 4 MW in future, a long baseline neutrino oscillation experiment with Hyper-Kamiokande as a far detector will open the possibility of measuring CP violation in the neutrino sector. Also, Hyper-Kamiokande will allow to extend nucleon decay search to τ p /B(p → e + π 0 ) > 10 35 yr and [Formula: see text]. Aiming at the realization of Hyper-Kamiokande, various R&D efforts are in progress.