Speaker
Description
Grand Unified Theories (GUTs) viewed as the extension of Standard Model (SM) are proposed and unify the strong, weak, and electromagnetic interactions at the order of $10^{15}$-$10^{16}$ GeV which is unreachable by accelerators. Since the three interactions are described by a single coupling constant in the GUTs, the violation of baryon number is allowed, and rare processes such as proton decay are predicted as one of the most important signatures. To probe the processes, Super-Kamiokande (SK) is a large water Cherenkov detector which is designed for precise observation of neutrinos and search for proton decay.
In order to search for the direct evidence of GUTs, two simplest general 2-body decays are considered. We search for $p→l^{+}+X$ (where $l^{+}$ is a positron or an antimuon, and $X$ is a neutral massless and invisible particle) using the entire pure water detector phase of SK (0.401 Mton∙year). By performing a spectral fit technique, new results are set for $p→e^{+}+X$ and $p→μ^{+}+X$, respectively.
