Search for Trilepton Nucleon Decay via $p\to e^{+}\nu \nu$ and $p\to {\mu }^{+}\nu \nu$ in the Super-Kamiokande Experiment

The trilepton nucleon decay modes $p\to e^{+}\nu \nu$ and $p \rightarrow \mu^+ \nu \nu$violate$|\Delta (B - L)|$ 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 ${\tau }_{p\to e^{+}\nu \nu }>1.7\times {10}^{32}$ years and ${\tau }_{p\to {\mu }^{+}\nu \nu }>2.2\times {10}^{32}$ years at a $90\mathrm{\%}$ confidence level are obtained. These limits can constrain Grand Unified Theories which allow for such processes.