title: Indications of neutrino oscillation in a 250 km long-baseline experiment.
abstract: The K2K experiment observes indications of neutrino oscillation: a reduction of nu(mu) flux together with a distortion of the energy spectrum. Fifty-six beam neutrino events are observed in Super-Kamiokande (SK), 250 km from the neutrino production point, with an expectation of 80.1(+6.2)(-5.4). Twenty-nine one ring mu-like events are used to reconstruct the neutrino energy spectrum, which is better matched to the expected spectrum with neutrino oscillation than without. The probability that the observed flux at SK is explained by statistical fluctuation without neutrino oscillation is less than 1%.
authors.affiliation: Department of Physics, Seoul National University, Seoul 151-742, Korea.
authors.forename: M H
authors.initials: MH
authors.lastname: Ahn
authors.forename: S
authors.initials: S
authors.lastname: Aoki
authors.forename: H
authors.initials: H
authors.lastname: Bhang
authors.forename: S
authors.initials: S
authors.lastname: Boyd
authors.forename: D
authors.initials: D
authors.lastname: Casper
authors.forename: J H
authors.initials: JH
authors.lastname: Choi
authors.forename: S
authors.initials: S
authors.lastname: Fukuda
authors.forename: Y
authors.initials: Y
authors.lastname: Fukuda
authors.forename: W
authors.initials: W
authors.lastname: Gajewski
authors.forename: T
authors.initials: T
authors.lastname: Hara
authors.forename: M
authors.initials: M
authors.lastname: Hasegawa
authors.forename: T
authors.initials: T
authors.lastname: Hasegawa
authors.forename: Y
authors.initials: Y
authors.lastname: Hayato
authors.forename: J
authors.initials: J
authors.lastname: Hill
authors.forename: A K
authors.initials: AK
authors.lastname: Ichikawa
authors.forename: A
authors.initials: A
authors.lastname: Ikeda
authors.forename: T
authors.initials: T
authors.lastname: Inagaki
authors.forename: T
authors.initials: T
authors.lastname: Ishida
authors.forename: T
authors.initials: T
authors.lastname: Ishii
authors.forename: M
authors.initials: M
authors.lastname: Ishitsuka
authors.forename: Y
authors.initials: Y
authors.lastname: Itow
authors.forename: T
authors.initials: T
authors.lastname: Iwashita
authors.forename: H I
authors.initials: HI
authors.lastname: Jang
authors.forename: J S
authors.initials: JS
authors.lastname: Jang
authors.forename: E J
authors.initials: EJ
authors.lastname: Jeon
authors.forename: C K
authors.initials: CK
authors.lastname: Jung
authors.forename: T
authors.initials: T
authors.lastname: Kajita
authors.forename: J
authors.initials: J
authors.lastname: Kameda
authors.forename: K
authors.initials: K
authors.lastname: Kaneyuki
authors.forename: I
authors.initials: I
authors.lastname: Kato
authors.forename: E
authors.initials: E
authors.lastname: Kearns
authors.forename: A
authors.initials: A
authors.lastname: Kibayashi
authors.forename: D
authors.initials: D
authors.lastname: Kielczewska
authors.forename: K
authors.initials: K
authors.lastname: Kobayashi
authors.forename: B J
authors.initials: BJ
authors.lastname: Kim
authors.forename: C O
authors.initials: CO
authors.lastname: Kim
authors.forename: J Y
authors.initials: JY
authors.lastname: Kim
authors.forename: S B
authors.initials: SB
authors.lastname: Kim
authors.forename: T
authors.initials: T
authors.lastname: Kobayashi
authors.forename: M
authors.initials: M
authors.lastname: Kohama
authors.forename: Y
authors.initials: Y
authors.lastname: Koshio
authors.forename: W R
authors.initials: WR
authors.lastname: Kropp
authors.forename: J G
authors.initials: JG
authors.lastname: Learned
authors.forename: S H
authors.initials: SH
authors.lastname: Lim
authors.forename: I T
authors.initials: IT
authors.lastname: Lim
authors.forename: H
authors.initials: H
authors.lastname: Maesaka
authors.forename: K
authors.initials: K
authors.lastname: Martens
authors.forename: T
authors.initials: T
authors.lastname: Maruyama
authors.forename: S
authors.initials: S
authors.lastname: Matsuno
authors.forename: C
authors.initials: C
authors.lastname: Mauger
authors.forename: C
authors.initials: C
authors.lastname: McGrew
authors.forename: S
authors.initials: S
authors.lastname: Mine
authors.forename: M
authors.initials: M
authors.lastname: Miura
authors.forename: K
authors.initials: K
authors.lastname: Miyano
authors.forename: S
authors.initials: S
authors.lastname: Moriyama
authors.forename: M
authors.initials: M
authors.lastname: Nakahata
authors.forename: K
authors.initials: K
authors.lastname: Nakamura
authors.forename: I
authors.initials: I
authors.lastname: Nakano
authors.forename: F
authors.initials: F
authors.lastname: Nakata
authors.forename: T
authors.initials: T
authors.lastname: Nakaya
authors.forename: S
authors.initials: S
authors.lastname: Nakayama
authors.forename: T
authors.initials: T
authors.lastname: Namba
authors.forename: K
authors.initials: K
authors.lastname: Nishikawa
authors.forename: S
authors.initials: S
authors.lastname: Nishiyama
authors.forename: S
authors.initials: S
authors.lastname: Noda
authors.forename: A
authors.initials: A
authors.lastname: Obayashi
authors.forename: A
authors.initials: A
authors.lastname: Okada
authors.forename: T
authors.initials: T
authors.lastname: Ooyabu
authors.forename: Y
authors.initials: Y
authors.lastname: Oyama
authors.forename: M Y
authors.initials: MY
authors.lastname: Pac
authors.forename: H
authors.initials: H
authors.lastname: Park
authors.forename: M
authors.initials: M
authors.lastname: Sakuda
authors.forename: N
authors.initials: N
authors.lastname: Sakurai
authors.forename: N
authors.initials: N
authors.lastname: Sasao
authors.forename: K
authors.initials: K
authors.lastname: Scholberg
authors.forename: E
authors.initials: E
authors.lastname: Sharkey
authors.forename: M
authors.initials: M
authors.lastname: Shiozawa
authors.forename: H
authors.initials: H
authors.lastname: So
authors.forename: H W
authors.initials: HW
authors.lastname: Sobel
authors.forename: A
authors.initials: A
authors.lastname: Stachyra
authors.forename: J L
authors.initials: JL
authors.lastname: Stone
authors.forename: Y
authors.initials: Y
authors.lastname: Suga
authors.forename: L R
authors.initials: LR
authors.lastname: Sulak
authors.forename: A
authors.initials: A
authors.lastname: Suzuki
authors.forename: Y
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Y
authors.initials: Y
authors.lastname: Takeuchi
authors.forename: N
authors.initials: N
authors.lastname: Tamura
authors.forename: T
authors.initials: T
authors.lastname: Toshito
authors.forename: Y
authors.initials: Y
authors.lastname: Totsuka
authors.forename: M R
authors.initials: MR
authors.lastname: Vagins
authors.forename: C W
authors.initials: CW
authors.lastname: Walter
authors.forename: R J
authors.initials: RJ
authors.lastname: Wilkes
authors.forename: S
authors.initials: S
authors.lastname: Yamada
authors.forename: S
authors.initials: S
authors.lastname: Yamamoto
authors.forename: C
authors.initials: C
authors.lastname: Yanagisawa
authors.forename: H
authors.initials: H
authors.lastname: Yokoyama
authors.forename: J
authors.initials: J
authors.lastname: Yoo
authors.forename: M
authors.initials: M
authors.lastname: Yoshida
authors.forename: J
authors.initials: J
authors.lastname: Zalipska