Hyper-Kamiokande, the next generation of water Cherenkov neutrino observatory, will open fascinating new window on the universe, including the search for Grand Unified Theory through proton decay, neutrino astronomy, and determination of the CP violation in the lepton sector. In the first part of this seminar, we will present some questions remaining in these various physics domains, as well as the answers we may be able to provide with Hyper-Kamiokande.
We will then discuss how to broaden the physics program of Hyper-Kamiokande. In order to detect the weak Cherenkov light generated by neutrino interactions or proton decay, the primary photo-detector candidate for Hyper-Kamiokande are 20-inch photomultiplier tubes. Complementarily, the collaboration is now studying to use also another type of photo-sensor, the multi-PMT modules. These modules, which were primarily developed for KM3NeT and are also the primary candidate for the future Hyper Kamiokande near detector, offers several advantages as higher sensitive surface, weaker sensitivity to Earth’s magnetic field, increased granularity, reduced dark rate, improved timing resolution and directional information with an almost isotropic field of view. We will present the modules developed for Hyper-Kamiokande and show the status of their developments and tests. We will conclude this seminar by presenting the very first studies showing how these multi-PMTs would impact Hyper-Kamiokande physics.