Search for Proton Decay into Muon plus Neutral Kaon in Super-Kamiokande I, II, and III

TL;DR

This study searched for proton decay into a muon and neutral kaon using extensive Super-Kamiokande data, finding no evidence but setting a new lower limit on the proton's lifetime in this decay mode.

Contribution

First comprehensive search for proton decay into muon plus neutral kaon across multiple Super-Kamiokande phases, establishing a new lower lifetime limit.

Findings

No candidate events observed beyond background expectations.

Set a lower limit on proton lifetime of 1.6×10^33 years.

Data consistent with atmospheric neutrino background.

Abstract

We have searched for proton into muon plus neutral kaon using data from a 91.7 kiloton-year exposure of Super-Kamiokande-I, a 49.2 kiloton-year exposure of Super-Kamiokande-II, and a 31.9 kiloton-year exposure of Super-Kamiokande-III. The number of candidate events in the data was consistent with the atmospheric neutrino background expectation and no evidence for proton decay in this mode was found. We set a partial lifetime lower limit of 1.6x10^33 years at the 90% confidence level.