Search for Trilepton Nucleon Decay via $p\to e^{+}\hat{I}½\hat{I}½$ and $p\to \hat{I}{¼}^{+}\hat{I}½\hat{I}½$ in the Super-Kamiokande Experiment

Abstract

The trilepton nucleon decay modes $p\to e^{+}\hat{I}½\hat{I}½$ and $p\to \hat{I}{¼}^{+}\hat{I}½\hat{I}½$ violate $|\hat{I}”(B-L)|$ by two units. Using data from a 273.4 kiloton year exposure of Super-Kamiokande a search for these decays yields a fit consistent with no signal. Accordingly, lower limits on the partial lifetimes of $\ddot{I}{„}_{p\to e^{+}\hat{I}½\hat{I}½}>1.7\times 10^{32}$ years and $\ddot{I}{„}_{p\to \hat{I}{¼}^{+}\hat{I}½\hat{I}½}>2.2\times 10^{32}$ years at a $90\%$ confidence level are obtained. These limits can constrain Grand Unified Theories which allow for such processes.