Search for Proton Decay viap→e+π0in a Large Water Cherenkov Detector

Abstract

We have searched for proton decay via $p\to e^{+}{\pi }^0$ using data from a $25.5\mathrm{kton}̇\mathrm{yr}$ exposure of the Super-Kamiokande detector. We find no candidate events with an expected background induced by atmospheric neutrinos of 0.1 events. From these data, we set a lower limit on the partial lifetime of the proton $\tau {/B}_{p\to e^{+}{\pi }^0}$ to be $1.6\times {10}^{33}\mathrm{years}$ at a 90% confidence level.