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

Understand

The trilepton nucleon decay modes $p \rightarrow e^+ \nu \nu$ 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 $\tau_{p \rightarrow e^+ \nu \nu} > 1.7 \times 10^{32}$ years and $\tau_{p \rightarrow \mu^+ \nu \nu} > 2.2 \times 10^{32}$ years at a $90 \% $ confidence level are obtained.
• These limits can constrain Grand Unified Theories which allow for such processes.