Phys. Rev. Lett.
81,
3319–3323
(1998)
Search for Proton Decay via p→e+π0 in a Large Water Cherenkov Detector
M. Shiozawa et al. (Super-Kamiokande Collaboration)
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M. Shiozawa1, B. Viren15, Y. Fukuda1, T. Hayakawa1, E. Ichihara1, K. Inoue1, K. Ishihara1, H. Ishino1, Y. Itow1, T. Kajita1, J. Kameda1, S. Kasuga1, K. Kobayashi1, Y. Kobayashi1, Y. Koshio1, M. Miura1, M. Nakahata1, S. Nakayama1, A. Okada1, M. Oketa1, K. Okumura1, M. Ota1, N. Sakurai1, Y. Suzuki1, Y. Takeuchi1, Y. Totsuka1, S. Yamada1, M. Earl2, A. Habig2, E. Kearns2, M. D. Messier2, K. Scholberg2, J. L. Stone2, L. R. Sulak2, C. W. Walter2, M. Goldhaber3, T. Barszczak4, W. Gajewski4, P. G. Halverson4,*, J. Hsu4, W. R. Kropp4, L. R. Price4, F. Reines4, H. W. Sobel4, M. R. Vagins4, K. S. Ganezer5, W. E. Keig5, R. W. Ellsworth6, S. Tasaka7, J. W. Flanagan8,†, A. Kibayashi8, J. G. Learned8, S. Matsuno8, V. Stenger8, D. Takemori8, T. Ishii9, J. Kanzaki9, T. Kobayashi9, K. Nakamura9, K. Nishikawa9, Y. Oyama9, A. Sakai9, M. Sakuda9, O. Sasaki9, S. Echigo10, M. Kohama10, A. T. Suzuki10, T. J. Haines11,4, E. Blaufuss12, R. Sanford12, R. Svoboda12, M. L. Chen13, Z. Conner13,‡, J. A. Goodman13, G. W. Sullivan13, M. Mori14,§, J. Hill15, C. K. Jung15, K. Martens15, C. Mauger15, C. McGrew15, E. Sharkey15, C. Yanagisawa15, W. Doki16, T. Ishizuka16,**, Y. Kitaguchi16, H. Koga16, K. Miyano16, H. Okazawa16, C. Saji16, M. Takahata16, A. Kusano17, Y. Nagashima17, M. Takita17, T. Yamaguchi17, M. Yoshida17, S. B. Kim18, M. Etoh19, K. Fujita19, A. Hasegawa19, T. Hasegawa19, S. Hatakeyama19, T. Iwamoto19, T. Kinebuchi19, M. Koga19, T. Maruyama19, H. Ogawa19, A. Suzuki19, F. Tsushima19, M. Koshiba20, M. Nemoto21, K. Nishijima21, T. Futagami22, Y. Hayato22,††, Y. Kanaya22, K. Kaneyuki22, Y. Watanabe22, D. Kielczewska23,4, R. Doyle24, J. George24, A. Stachyra24, L. Wai24, J. Wilkes24, and K. Young24 (Super-Kamiokande Collaboration)
1Institute for Cosmic Ray Research, University of Tokyo, Tanashi, Tokyo 188-8502, Japan
2Department of Physics, Boston University, Boston, Massachusetts 02215
3Physics Department, Brookhaven National Laboratory, Upton, New York 11973
4Department of Physics and Astronomy, University of California—Irvine, Irvine, California 92697-4575
5Department of Physics, California State University, Dominguez Hills, Carson, California 90747
6Department of Physics, George Mason University, Fairfax, Virginia 22030
7Department of Physics, Gifu University, Gifu, Gifu 501-1193, Japan
8Department of Physics and Astronomy, University of Hawaii, Honolulu, Hawaii 96822
9Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan
10Department of Physics, Kobe University, Kobe, Hyogo 657-8501, Japan
11Physics Division, P-23, Los Alamos National Laboratory, Los Alamos, New Mexico 87544
12Physics Department, Louisiana State University, Baton Rouge, Louisiana 70803
13Department of Physics, University of Maryland, College Park, Maryland 20742
14Department of Physics, Miyagi University of Education, Sendai, Miyagi 980-0845, Japan
15Department of Physics and Astronomy, State University of New York, Stony Brook, New York 11794-3800
16Department of Physics, Niigata University, Niigata, Niigata 950-2181, Japan
17Department of Physics, Osaka University, Toyonaka, Osaka 560-0043, Japan
18Department of Physics, Seoul National University, Seoul 151-742, Korea
19Department of Physics, Tohoku University, Sendai, Miyagi 980-8578, Japan
20The University of Tokyo, Tokyo 113-0033, Japan
21Department of Physics, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan
22Department of Physics, Tokyo Institute for Technology, Meguro, Tokyo 152-8551, Japan
23Institute of Experimental Physics, Warsaw University, 00-681 Warsaw, Poland
24Department of Physics, University of Washington, Seattle, Washington 98195-1560
Received 19 May 1998; published in the issue dated 19 October 1998
We have searched for proton decay via p→e+π0 using data from a 25.5ktoṅyr 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 τ/Bp→e+π0 to be 1.6×1033years at a 90% confidence level.
© 1998 The American Physical Society
URL:
http://link.aps.org/doi/10.1103/PhysRevLett.81.3319
DOI:
10.1103/PhysRevLett.81.3319
PACS:
13.30.Ce, 11.30.Fs, 14.20.Dh, 29.40.Ka
*Present address: NASA, JPL, Pasadena, CA 91109. †Present address: Accelerator Laboratory, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan. ‡Present address: Enrico Fermi Institute, University of Chicago, Chicago, IL 60637. §Present address: Institute for Cosmic Ray Research, University of Tokyo, Tanashi, Tokyo 188-8502, Japan. **Present address: Dept. of System Engineering, Shizuoka University, Hamakita, Shizuoka 432-8561, Japan. ††Present address: Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan.
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