Abe, K; Hayato, Y; Iida, T; Ishihara, K; Kameda, J; Koshio, Y; Minamino, A; Mitsuda, C; Miura, M; Moriyama, S; Nakahata, M; Obayashi, Y; Ogawa, H; Sekiya, H; Shiozawa, M; Suzuki, Y; Takeda, A; Takeuchi, Y; Ueshima, K; Watanabe, H; Higuchi, I; Ishihara, C; Ishitsuka, M; Kajita, T; Kaneyuki, K; Mitsuka, G; Nakayama, S; Nishino, H; Okumura, K; Saji, C; Takenaga, Y; Clark, S; Desai, S; Dufour, F; Herfurth, A; Kearns, E; Likhoded, S; Litos, M; Raaf, JL; Stone, JL; Sulak, LR; Wang, W; Goldhaber, M; Casper, D; Cravens, JP; Dunmore, J; Griskevich, J; Kropp, WR; Liu, DW; Mine, S; Regis, C; Smy, MB; Sobel, HW; Vagins, MR; Ganezer, KS; Hartfiel, B; Hill, J; Keig, WE; Jang, JS; Jeoung, IS; Kim, JY; Lim, IT; Scholberg, K; Tanimoto, N; Walter, CW; Wendell, R; Ellsworth, RW; Tasaka, S; Guillian, G; Learned, JG; Matsuno, S; Messier, MD; Ichikawa, AK; Ishida, T; Ishii, T; Iwashita, T; Kobayashi, T; Nakadaira, T; Nakamura, K; Nishikawa, K; Nitta, K; Oyama, Y; Suzuki, AT; Hasegawa, M; Maesaka, H; Nakaya, T; Sasaki, T; Sato, H; Tanaka, H; Yamamoto, S; Yokoyama, M; Haines, TJ; Dazeley, S; Hatakeyama, S; Svoboda, R; Sullivan, GW; Gran, R; Habig, A; Fukuda, Y; Itow, Y; Koike, T; Jung, CK; Kato, T; Kobayashi, K; McGrew, C; Sarrat, A; Terri, R; Yanagisawa, C; Tamura, N; Ikeda, M; Sakuda, M; Kuno, Y; Yoshida, M; Kim, SB; Yang, BS; Ishizuka, T; Okazawa, H; Choi, Y; Seo, HK; Gando, Y; Hasegawa, T; Inoue, K; Ishii, H; Nishijima, K; Ishino, H; Watanabe, Y; Koshiba, M; Totsuka, Y; Chen, S; Deng, Z; Liu, Y; Kielczewska, D; Berns, HG; Shiraishi, KK; Thrane, E; Washburn, K; Wilkes, RJ, Search for oscillation in Super-Kamiokande,
Physical Review D, vol. 91 no. 7
(April, 2015),
pp. 072006 [doi] .
Abstract:
A search for neutron-antineutron ($n-\bar{n}$) oscillation was undertaken in
Super-Kamiokande using the 1489 live-day or $2.45 \times 10^{34}$ neutron-year
exposure data. This process violates both baryon and baryon minus lepton
numbers by an absolute value of two units and is predicted by a large class of
hypothetical models where the seesaw mechanism is incorporated to explain the
observed tiny neutrino masses and the matter-antimatter asymmetry in the
Universe. No evidence for $n-\bar{n}$ oscillation was found, the lower limit of
the lifetime for neutrons bound in ${}^{16}$O, in an analysis that included all
of the significant sources of experimental uncertainties, was determined to be
$1.9 \times 10^{32}$~years at the 90\% confidence level. The corresponding
lower limit for the oscillation time of free neutrons was calculated to be $2.7
\times 10^8$~s using a theoretical value of the nuclear suppression factor of
$0.517 \times 10^{23}$~s$^{-1}$ and its uncertainty.