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

We have searched for proton decay via $p\ensuremath{\rightarrow}{e}^{+}{\ensuremath{\pi}}^{0}$ using data from a $25.5\mathrm{kton}\ifmmode \dot{}\else \.{}\fi{}\mathrm{yr}$ 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 $\ensuremath{\tau}{/B}_{p\ensuremath{\rightarrow}{e}^{+}{\ensuremath{\pi}}^{0}}$ to be $1.6\ifmmode\times\else\texttimes\fi{}{10}^{33}\mathrm{years}$ at a 90% confidence level.