Search for proton decay into e sup + +. pi. sup 0 in the IMB-3 detector

• Published in: Physical review. D, Particles and fields Vol. 42:9
• Main Authors: Becker-Szendy, R., Bratton, C.B., Cady, D.R., Casper, D., Claus, R., Crouch, M., Dye, S.T., Gajewski, W., Goldhaber, M., Haines, T.J., Halverson, P.G., Jones, T.W., Kielczewska, D., Kropp, W.R., Learned, J.G., LoSecco, J.M., McGrew, C., Matsuno, S., Mudan, M.S., Price, L., Reines, F., Schultz, J., Sinclair, D., Sobel, H.W., Stone, J.L., Sulak, L.R., Svoboda, R., Thornton, G., van der Velde, J.C.
• Format: Journal Article
• Language: English
• Published: United States 01-11-1990
• Subjects: 645102 - High Energy Physics- Particle Interactions & Properties-Experimental- Weak Interactions & Properties; ANTILEPTONS; ANTIMATTER; ANTIPARTICLES; BARYONS; BOSONS; CHERENKOV COUNTERS; DECAY; ELEMENTARY PARTICLES; FERMIONS; FIELD THEORIES; GRAND UNIFIED THEORY; HADRONS; LEPTONS; LIFETIME; MASSLESS PARTICLES; MATHEMATICAL MODELS; MEASURING INSTRUMENTS; MESONS; MUONS; MUONS PLUS; NEUTRINOS; NEUTRONS; NUCLEONS; PARTICLE MODELS; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; PIONS; PIONS MINUS; PIONS NEUTRAL; PIONS PLUS; POSITRONS; PROTONS; PSEUDOSCALAR MESONS; RADIATION DETECTORS; SUPERSYMMETRY; SYMMETRY; UNIFIED GAUGE MODELS; UNIFIED-FIELD THEORIES
• ISSN: 0556-2821; 1089-4918
• DOI: 10.1103/PhysRevD.42.2974

We report the results of a search for proton decay into {ital e}{sup +}+{pi}{sup 0} in the 6800-ton IMB-3 water Cherenkov detector. During 376 days of live time no events consistent with this decay were found in the 3300 ton fiducial volume. From this observation we derive a limit on the partial lifetime to be {tau}/{ital B}{gt}2.4{times}10{sup 32} yr (90% C.L.), which, combined with our previous result of 3.1{times}10{sup 32} yr, provides a limit of 5.5{times}10{sup 32} yr. The general features of the observed contained events are compatible with those expected from atmospheric neutrino interactions.