Beam Background Monitors for the Belle II Experiment

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The Belle II experiment will be located at the SuperKEKB e+e- collider at the KEK laboratory in Tsukuba, Japan. It is the successor to the successful Belle and BaBar experiments, which were cited for their contributions to the phenomenon of CP violation in the 2008 Nobel Prize in Physics. The primary physics goal of Belle II is to search for evidence of new physics through a wide range of measurements that are sensitive to the presence of heavy virtual particles, and that can be precisely predicted in the Standard Model. These measurements could include CP violation and other asymmetries, rare decays, or forbidden decays. The mass reach of these measurements can exceed that of the direct searches by ATLAS and CMS. If new physics is found at the LHC, Belle II can explore its nature by looking for a pattern of deviations from the Standard Model in ways that are not feasible at a hadron collider. If new physics is not discovered at the LHC, Belle II measurements will provide critical guidance towards beyond-the-standard-model theories by either discovering new phenomena and deviations from Standard Model expectations, or by excluding hypothesized models of new physics. Belle II will also be sensitive to the direct production of new light particles, including those predicted by dark sector models of dark matter, or additional Higgs particles, particles that will be difficult to detect at the LHC. The experiment will also continue the exploration of the weak force and CP violation, a program successfully followed by BaBar and Belle. The funds requested will enable the Canadian group to develop and provide permanent hardware for fast real-time SuperKEKB-beam background monitoring in the vicinity of the Belle II electromagnetic calorimeter. The system will consist of LYSO crystals, which are radiation hard and have fast-timing responses, thereby providing accelerator operators with sensitivity to quickly varying injection backgrounds manifesting in multiple particle types. Longevity of the system's operations over the lifetime of the Belle II experiment's run periods will be achieved by using a set of light guides to permit a single multiplexed photo-multiplication component to provide signal readout in a location with reduced radiation and magnetic-field levels, remote from the background detectors embedded inside the electromagnetic calorimeter's shielding. This research will further worldwide particle-physics knowledge of the fundamental constituents of matter in our Universe. The Canadian designed and built hardware in this request will constitute a part of the Belle II experiment and will provide unique training of highly qualified personnel, individuals with enhanced capacity to contribute to future Canadian knowledge acquisition and economically beneficial innovation in the private and public sectors.