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

TL;DR

This study searches for rare proton decay modes involving three leptons in Super-Kamiokande data, setting new lower bounds on their lifetimes to constrain grand unified theories.

Contribution

First search for proton decay modes $p ightarrow e^+ u u$ and $p ightarrow  u u$ using Super-Kamiokande data, establishing new lifetime limits.

Findings

No evidence of the decay modes was observed.

Lower lifetime limits are set at $1.7 imes 10^{32}$ and $2.2 imes 10^{32}$ years.

Results constrain certain grand unified theories.

Abstract

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.