Grant: Subatomic Physics Envelope - Project

The Hyper-Kamiokande (Hyper-K) experiment is a next-generation neutrino experiment and astrophysical observatory.  The Hyper-K experiment will be used to study the fundamental nature of the universe, particularly through measurements of the process of neutrino oscillations and the study of how neutrino oscillations may introduce an asymmetry between matter and antimatter called CP violation.  The Hyper-K experiment has a broad physics program that also includes the study of atmospheric, solar and supernova neutrinos, and searches for nucleon decay and dark matter.  Hyper-K will achieve significant improvements over the current generation of experiments, T2K and Super-K, by having an 8-times larger detector, and a 2.5-times more intense neutrino beam.  The Hyper-K experiment was approved by Japan in 2020 and construction is proceeding on schedule. The Hyper-K Canada group aims to control critical uncertainties for Hyper-K measurements. One challenge is the accurate description of neutrino interactions in the detector. The Intermediate Water Cherenkov Detector (IWCD) will make neutrino measurements at different positions in order to probe the relationship between neutrino energy and what is observed in the detector. The Canadian team is leading the development of an IWCD prototype detector, called the Water Cherenkov Test Experiment, the will be operated at CERN. Canadian contributions to IWCD and WCTE include novel photon detectors, photogrammetry based position calibration, water quality monitoring and measurements of photon detector properties. In Hyper-K, the other dominant uncertainties are on the modelling of the water quality and the response of photon detectors. Photon detectors with pulsed LED light injection will be used to probe both the water quality and photon detector response. This will take advantage of newly developed sub-nanosecond LED pulsers from the University of Victoria. These measurements will be supported by the photogrammetry positioning system and ex-situ measurements of both the water quality and PMT response.   The Hyper-K Canada group has led the development of machine learning techniques for calibration and event reconstruction in water Cherenkov detectors. The Hyper-K Canada group also maintains a presence in the Super-Kamiokande experiment, where photogrammetry, ex-situ PMT measurements and machine learning techniques are being applied and tested in calibration and event reconstruction. This proposal will support the activities of the Hyper-K Canada group as it completes the development of detector systems for WCTE, IWCD and Hyper-K; builds and operates the WCTE and analyzes WCTE data; produces the detector systems for IWCD and Hyper-K; begins the installation of these systems for the Hyper-K experiment.; and continues participation in the Super-K experiment while developing calibration and data analysis techniques.