Speaker
Description
The Hyper-Kamiokande experiment (HK), scheduled to start in 2028, aims to discover nucleon decay predicted by many Grand Unified Theories (GUTs). The ongoing Super-Kamiokande (SK) experiment has been searching for such events, but no sign of proton decay has been observed yet.
In this work, we estimate the HK search sensitivity to the $p\to\bar{\nu}K^+$, a primary mode predicted by the SUSY motivated GUTs, such as SUSY SU(5). The produced kaon’s momentum is below the Cherenkov threshold, so decay products of kaon are used to reconstruct the event. This study focuses on the $K^+\to\mu^+\nu_\mu$ mode.
For background reduction, in addition to requiring a muon, we applied criteria based on the number of PMT hits from de-excitation gamma rays stochastically emitted from the residual nucleus following proton decay, a technique also used in SK. This condition effectively suppresses atmospheric neutrino background events, particularly charged-current quasi-elastic (CCQE) interactions, which are difficult to reject by muon selection alone.
This poster presents the analysis methodology and the estimated HK search sensitivity derived from the final signal and background events.