Search for proton decay through p->\bar{\nu} K^+ in a large water Cherenkov detector

TL;DR

This study searches for proton decay via p→ν̄K+ in a large water Cherenkov detector, setting new lower limits on proton lifetime and analyzing specific kaon decay modes with extensive data.

Contribution

It provides the first comprehensive search for p→ν̄K+ decay mode using Super-Kamiokande data, establishing new lifetime limits and analyzing multiple kaon decay channels.

Findings

No evidence of proton decay observed.

Lower limit on proton lifetime: 6.7×10^32 years.

Results consistent with atmospheric neutrino background.

Abstract

We present results of a search for proton decays, $p \to \bar{\nu} K^+$, using data from a 33 kton$\cdot$year exposure of the Super-Kamiokande detector. Two decay modes of the kaon, $K^+ \to \mu^+ \nu_{\mu}$ and $K^+ \to \pi^+ \pi^0$, were studied. The data were consistent with the background expected from atmospheric neutrinos; therefore a lower limit on the partial lifetime of the proton $\tau / B(p \to \bar{\nu} K^+)$ was found to be $6.7 \times 10^{32}$ years at 90% confidence level.