K
Ken-ichiro Kobayashi
Researcher at University of Tokyo
Publications - 69
Citations - 11815
Ken-ichiro Kobayashi is an academic researcher from University of Tokyo. The author has contributed to research in topics: Neutrino & Super-Kamiokande. The author has an hindex of 33, co-authored 69 publications receiving 11192 citations. Previous affiliations of Ken-ichiro Kobayashi include Institute for the Physics and Mathematics of the Universe & University of Rochester.
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Journal ArticleDOI
Evidence for oscillation of atmospheric neutrinos
Y. Fukuda,T. Hayakawa,E. Ichihara,Kunio Inoue,K. Ishihara,H. Ishino,Yoshitaka Itow,Takaaki Kajita,J. Kameda,S. Kasuga,Ken-ichiro Kobayashi,Yohei Kobayashi,Yusuke Koshio,M. Miura,Masayuki Nakahata,S. Nakayama,A. Okada,Ko Okumura,N. Sakurai,Masato Shiozawa,Yoshihiro Suzuki,Y. Takeuchi,Y. Totsuka,Shinya Yamada,M. Earl,Alec Habig,E. Kearns,M. D. Messier,Kate Scholberg,J. L. Stone,Lawrence Sulak,C. W. Walter,M. Goldhaber,T. Barszczxak,D. Casper,W. Gajewski,P. G. Halverson,J. Hsu,W. R. Kropp,L. R. Price,Frederick Reines,Michael B. Smy,Henry W. Sobel,Mark R. Vagins,K. S. Ganezer,W. E. Keig,R. W. Ellsworth,S. Tasaka,J. W. Flanagan,A. Kibayashi,John G. Learned,S. Matsuno,V. J. Stenger,D. Takemori,T. Ishii,Junichi Kanzaki,T. Kobayashi,S. Mine,K. Nakamura,K. Nishikawa,Yuichi Oyama,A. Sakai,Makoto Sakuda,Osamu Sasaki,S. Echigo,M. Kohama,A. T. Suzuki,Todd Haines,Todd Haines,E. Blaufuss,B. K. Kim,R. Sanford,R. Svoboda,M. L. Chen,Z. Conner,Z. Conner,J. A. Goodman,G. W. Sullivan,J. Hill,C. K. Jung,K. Martens,C. Mauger,C. McGrew,E. Sharkey,B. Viren,C. Yanagisawa,W. Doki,Kazumasa Miyano,H. Okazawa,C. Saji,M. Takahata,Y. Nagashima,M. Takita,Takashi Yamaguchi,Minoru Yoshida,Soo-Bong Kim,M. Etoh,K. Fujita,Akira Hasegawa,Takehisa Hasegawa,S. Hatakeyama,T. Iwamoto,M. Koga,Tomoyuki Maruyama,Hiroshi Ogawa,J. Shirai,A. Suzuki,F. Tsushima,Masatoshi Koshiba,M. Nemoto,Kyoshi Nishijima,T. Futagami,Y. Hayato,Y. Kanaya,K. Kaneyuki,Y. Watanabe,D. Kielczewska,D. Kielczewska,R. A. Doyle,J. S. George,A. L. Stachyra,L. Wai,L. Wai,R. J. Wilkes,K. K. Young +124 more
Abstract: We present an analysis of atmospheric neutrino data from a 33.0 kton yr (535-day) exposure of the Super-Kamiokande detector. The data exhibit a zenith angle dependent deficit of muon neutrinos which is inconsistent with expectations based on calculations of the atmospheric neutrino flux. Experimental biases and uncertainties in the prediction of neutrino fluxes and cross sections are unable to explain our observation. The data are consistent, however, with two-flavor ${\ensuremath{
u}}_{\ensuremath{\mu}}\ensuremath{\leftrightarrow}{\ensuremath{
u}}_{\ensuremath{\tau}}$ oscillations with ${sin}^{2}2\ensuremath{\theta}g0.82$ and $5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}l\ensuremath{\Delta}{m}^{2}l6\ifmmode\times\else\texttimes\fi{}1{0}^{\ensuremath{-}3}\mathrm{eV}{}^{2}$ at 90% confidence level.
Journal ArticleDOI
Room-temperature magnetoresistance in an oxide material with an ordered double-perovskite structure
TL;DR: In this paper, an ordered double perovskite (Sr2FeMoO) was shown to exhibit intrinsic tunnelling-type magnetoresistance at room temperature.
Journal ArticleDOI
Indications of neutrino oscillation in a 250 km long-baseline experiment.
M. H. Ahn,Shigeki Aoki,H. C. Bhang,S. B. Boyd,David William Casper,J. H. Choi,S. Fukuda,Y. Fukuda,W. Gajewski,T. Hara,Masaya Hasegawa,Takehisa Hasegawa,Y. Hayato,J. Hill,A. K. Ichikawa,A. Ikeda,T. Inagaki,T. Ishida,T. Ishii,M. Ishitsuka,Yoshitaka Itow,T. Iwashita,H. I. Jang,J. S. Jang,E. J. Jeon,C. K. Jung,Takaaki Kajita,J. Kameda,K. Kaneyuki,I. Kato,E. Kearns,A. Kibayashi,D. Kielczewska,Ken-ichiro Kobayashi,Beom Jun Kim,C. O. Kim,J. Y. Kim,S. B. Kim,Takashi Kobayashi,M. Kohama,Yusuke Koshio,W. R. Kropp,John G. Learned,S. H. Lim,I. T. Lim,H. Maesaka,K. Martens,Tomoyuki Maruyama,S. Matsuno,C. Mauger,C. McGrew,S. Mine,M. Miura,Kazumasa Miyano,Shigetaka Moriyama,Masayuki Nakahata,Koji Nakamura,Itsuo Nakano,F. Nakata,Tsuyoshi Nakaya,Shoei Nakayama,Toshio Namba,K. Nishikawa,Shogo Nishiyama,Susumu Noda,A. Obayashi,A. Okada,T. Ooyabu,Yuichi Oyama,M. Y. Pac,Hwangseo Park,Makoto Sakuda,Nobuyuki Sakurai,N. Sasao,Kate Scholberg,E. Sharkey,Masato Shiozawa,H. So,H. W. Sobel,A. L. Stachyra,J. L. Stone,Y. Suga,L. R. Sulak,Atsumu Suzuki,Yasunari Suzuki,Y. Takeuchi,N. Tamura,T. Toshito,Y. Totsuka,Mark R. Vagins,C. W. Walter,R. J. Wilkes,Shinya Yamada,Shoji Yamamoto,C. Yanagisawa,H. Yokoyama,J. Yoo,Minoru Yoshida,J. Zalipska +98 more
TL;DR: The K2K experiment observed indications of neutrino oscillation after 250 km flight of υμ. as mentioned in this paper The observed number of events in the data corresponding to 4.8 x 1019 protons on target is 56, while 80.1 5.4 + 6.2 is expected.
Journal ArticleDOI
Measurement of the Flux and Zenith-Angle Distribution of Upward Throughgoing Muons by Super-Kamiokande
Y. Fukuda,T. Hayakawa,E. Ichihara,Kunio Inoue,K. Ishihara,H. Ishino,Yoshitaka Itow,Takaaki Kajita,J. Kameda,S. Kasuga,Ken-ichiro Kobayashi,Y. Kobayashi,Yusuke Koshio,M. Miura,Masayuki Nakahata,Shoei Nakayama,A. Okada,Ko Okumura,Nobuyuki Sakurai,Masato Shiozawa,Yasunari Suzuki,Y. Takeuchi,Y. Totsuka,Shinya Yamada,M. Earl,Alec Habig,E. Kearns,M. D. Messier,Kate Scholberg,J. L. Stone,L. R. Sulak,C. W. Walter,M. Goldhaber,T. Barszczak,David William Casper,W. Gajewski,W. R. Kropp,L. R. Price,Frederick Reines,Michael B. Smy,H. W. Sobel,Mark R. Vagins,K. S. Ganezer,W. E. Keig,R. W. Ellsworth,S. Tasaka,J. W. Flanagan,A. Kibayashi,John G. Learned,S. Matsuno,V. J. Stenger,D. Takemori,T. Ishii,Junichi Kanzaki,T. Kobayashi,S. Mine,K. Nakamura,K. Nishikawa,Yuichi Oyama,A. Sakai,Makoto Sakuda,Osamu Sasaki,S. Echigo,M. Kohama,Atsumu Suzuki,Todd Haines,Todd Haines,E. Blaufuss,B. K. Kim,R. Sanford,R. Svoboda,M. L. Chen,J. A. Goodman,G. W. Sullivan,J. Hill,C. K. Jung,K. Martens,C. Mauger,C. McGrew,E. Sharkey,B. Viren,C. Yanagisawa,W. Doki,Kazumasa Miyano,H. Okazawa,C. Saji,M. Takahata,Y. Nagashima,M. Takita,Takashi Yamaguchi,Minoru Yoshida,Soo-Bong Kim,M. Etoh,K. Fujita,Akira Hasegawa,Takehisa Hasegawa,S. Hatakeyama,T. Iwamoto,M. Koga,Tomoyuki Maruyama,Hiroshi Ogawa,J. Shirai,A. Suzuki,F. Tsushima,Masatoshi Koshiba,M. Nemoto,Kyoshi Nishijima,T. Futagami,Y. Hayato,Y. Kanaya,K. Kaneyuki,Y. Watanabe,D. Kielczewska,D. Kielczewska,R. A. Doyle,J. S. George,J. S. George,A. L. Stachyra,L. Wai,L. Wai,R. J. Wilkes,K. K. Young +121 more
TL;DR: A total of 614 upward throughgoing muons were observed by Super-Kamiokande during 537 detector live days and the measured muon flux is [1.74{plus_minus} 0.02(sys)]{times} 10{sup {minus}13} cm{sup 2}thinsp2{theta} {gt}0.
Journal ArticleDOI
Solar neutrino results in Super-Kamiokande-III
K. Abe,Y. Hayato,T. Iida,M. Ikeda,M. Ikeda,C. Ishihara,K. Iyogi,J. Kameda,Ken-ichiro Kobayashi,Yusuke Koshio,Y. Kozuma,M. Miura,S. Moriyama,Masayuki Nakahata,S. Nakayama,Y. Obayashi,H. Ogawa,Hiroyuki Sekiya,Masato Shiozawa,Yasunari Suzuki,Atsushi Takeda,Y. Takenaga,Koh Ueno,K. Ueshima,Hiroshi Watanabe,S. Yamada,T. Yokozawa,S. Hazama,H. Kaji,Takaaki Kajita,K. Kaneyuki,T. McLachlan,Ko Okumura,Y. Shimizu,N. Tanimoto,M. R. Vagins,M. R. Vagins,L. Labarga,L. M. Magro,Frédéric Dufour,E. Kearns,E. Kearns,Michael Litos,J. L. Raaf,J. L. Stone,J. L. Stone,L. R. Sulak,W. Wang,W. Wang,M. Goldhaber,K. Bays,David William Casper,J. P. Cravens,W. R. Kropp,S. Mine,C. Regis,A. L. Renshaw,M. B. Smy,M. B. Smy,H. W. Sobel,H. W. Sobel,K. S. Ganezer,John Hill,W. E. Keig,J. S. Jang,J. Y. Kim,I. T. Lim,Justin Albert,R. A. Wendell,T. Wongjirad,Kate Scholberg,Kate Scholberg,C. W. Walter,C. W. Walter,T. Ishizuka,S. Tasaka,John G. Learned,S. Matsuno,Y. Watanabe,Takehisa Hasegawa,T. Ishida,T. Ishii,T. Kobayashi,T. Nakadaira,Koji Nakamura,K. Nishikawa,H. Nishino,Yuichi Oyama,Ken Sakashita,T. Sekiguchi,T. Tsukamoto,A. T. Suzuki,Y. Takeuchi,Y. Takeuchi,A. Minamino,Tsuyoshi Nakaya,Tsuyoshi Nakaya,Y. Fukuda,Yoshitaka Itow,G. Mitsuka,T. Tanaka,C. K. Jung,G. D. Lopez,C. McGrew,R. Terri,C. Yanagisawa,N. Tamura,Hirokazu Ishino,A. Kibayashi,S. Mino,Takaaki Mori,Makoto Sakuda,H. Toyota,Y. Kuno,Minoru Yoshida,S. B. Kim,B. S. Yang,H. Okazawa,Y. Choi,K. Nishijima,Y. Yokosawa,M. Koshiba,Y. Totsuka,Masashi Yokoyama,Song Chen,Y. Heng,Zishuo Yang,Haoxiong Zhang,D. Kielczewska,P. Mijakowski,K. Connolly,M. Dziomba,E. Thrane,E. Thrane,R. J. Wilkes +134 more
TL;DR: The results of the third phase of the Super-Kamiokande solar neutrino measurement are presented and compared to the first and second phase results in this article, where improved detector calibrations, a full detector simulation, and improved analysis methods are estimated to be approximately 2.1%, which is about two thirds of the systematic uncertainty for the first phase.