Nishino, H; Clark, S; Abe, K; Hayato, Y; Iida, T; Ikeda, M; Kameda, J; Kobayashi, K; Koshio, Y; Miura, M; Moriyama, S; Nakahata, M; Nakayama, S; Obayashi, Y; Ogawa, H; Sekiya, H; Shiozawa, M; Suzuki, Y; Takeda, A; Takenaga, Y; Takeuchi, Y; Ueno, K; Ueshima, K; Watanabe, H; Yamada, S; Hazama, S; Higuchi, I; Ishihara, C; Kajita, T; Kaneyuki, K; Mitsuka, G; Okumura, K; Tanimoto, N; Vagins, MR; Dufour, F; Kearns, E; Litos, M; Raaf, JL; Stone, JL; Sulak, LR; Wang, W; Goldhaber, M; Dazeley, S; Svoboda, R; Bays, K; Casper, D; Cravens, JP; Kropp, WR; Mine, S; Regis, C; Smy, MB; Sobel, HW; Ganezer, KS; Hill, J; Keig, WE; Jang, JS; Kim, JY; Lim, IT; Fechner, M; Scholberg, K; Walter, CW; Wendell, R; Tasaka, S; Learned, JG; Matsuno, S; Watanabe, Y; Hasegawa, T; Ishida, T; Ishii, T; Kobayashi, T; Nakadaira, T; Nakamura, K; Nishikawa, K; Oyama, Y; Sakashita, K; Sekiguchi, T; Tsukamoto, T; Suzuki, AT; Minamino, A; Nakaya, T; Yokoyama, M; Fukuda, Y; Itow, Y; Tanaka, T; Jung, CK; Lopez, G; McGrew, C; Terri, R; Yanagisawa, C; Tamura, N; Idehara, Y; Sakuda, M; Kuno, Y; Yoshida, M; Kim, SB; Yang, BS; Ishizuka, T; Okazawa, H; Choi, Y; Seo, HK; Furuse, Y; Nishijima, K; Yokosawa, Y; Koshiba, M; Totsuka, Y; Chen, S; Heng, Y; Yang, Z; Zhang, H; Kielczewska, D; Thrane, E; Wilkes, RJ; Super-Kamiokande Collaboration,, Search for proton decay via p-->e+pi0 and p-->micro+pi0 in a large water Cherenkov detector.,
Physical Review Letters, vol. 102 no. 14
(April, 2009),
pp. 141801 [19392425], [doi] .
Abstract:
We have searched for proton decays via p-->e;{+}pi;0 and p-->micro;{+}pi;0 using data from a 91.7 kt.yr exposure of Super-Kamiokande-I and a 49.2 kt.yr exposure of Super-Kamiokande-II. No candidate events were observed with expected backgrounds induced by atmospheric neutrinos of 0.3 events for each decay mode. From these results, we set lower limits on the partial lifetime of 8.2 x 10;33 and 6.6 x 10;33 years at 90% confidence level for p-->e;{+}pi;0 and p-->micro;{+}pi;0 modes, respectively.