Evaluation of event reconstruction with small-scale water Cherenkov detectors

The Hyper-Kamiokande experiment is planned to start in 2027 aiming for precise measurement of neutrino oscillation using J-PARC neutrino beam including the search for CP violation in the lepton sector. The Hyper-Kamiokande detector is a 260 kiloton water Cherenkov detector. In order to achieve the precision measurement, systematic uncertainties should be suppressed. For this purpose, a new 1 kiloton scale Intermediate Water Cherenkov Detector (IWCD) is proposed to measure the neutrino flux and interaction cross section near the generation point of the neutrino beam before oscillation. Water Cherenkov Test Experiment (WCTE) is a 50 ton scale water Cherenkov detector and currently under preparation to validate the performance of IWCD. WCTE will use new photosensor called multi-PMT and study the response of small water Cherenkov detectors to electron, muon, and hadron beams at CERN. The performance of event reconstruction with the IWCD and WCTE detectors is evaluated using simulation.