Indications of neutrino oscillation in a 250 km long-baseline experiment

M H Ahn; S Aoki; H Bhang; S Boyd; D Casper; J H Choi; S Fukuda; Y Fukuda; W Gajewski; T Hara; M Hasegawa; T Hasegawa; Y Hayato; J Hill; A K Ichikawa; A Ikeda; T Inagaki; T Ishida; T Ishii; M Ishitsuka; Y Itow; T Iwashita; H I Jang; J S Jang; E J Jeon; C K Jung; T Kajita; J Kameda; K Kaneyuki; I Kato; E Kearns; A Kibayashi; D Kielczewska; K Kobayashi; B J Kim; C O Kim; J Y Kim; S B Kim; T Kobayashi; M Kohama; Y Koshio; W R Kropp; J G Learned; S H Lim; I T Lim; H Maesaka; K Martens; T Maruyama; S Matsuno; C Mauger; C McGrew; S Mine; M Miura; K Miyano; S Moriyama; M Nakahata; K Nakamura; I Nakano; F Nakata; T Nakaya; S Nakayama; T Namba; K Nishikawa; S Nishiyama; S Noda; A Obayashi; A Okada; T Ooyabu; Y Oyama; M Y Pac; H Park; M Sakuda; N Sakurai; N Sasao; K Scholberg; E Sharkey; M Shiozawa; H So; H W Sobel; A Stachyra; J L Stone; Y Suga; L R Sulak; A Suzuki; Y Suzuki; Y Takeuchi; N Tamura; T Toshito; Y Totsuka; M R Vagins; C W Walter; R J Wilkes; S Yamada; S Yamamoto; C Yanagisawa; H Yokoyama; J Yoo; M Yoshida; J Zalipska

doi:10.1103/PhysRevLett.90.041801

Indications of neutrino oscillation in a 250 km long-baseline experiment

Phys Rev Lett. 2003 Jan 31;90(4):041801. doi: 10.1103/PhysRevLett.90.041801. Epub 2003 Jan 30.

Authors

M H Ahn¹, S Aoki, H Bhang, S Boyd, D Casper, J H Choi, S Fukuda, Y Fukuda, W Gajewski, T Hara, M Hasegawa, T Hasegawa, Y Hayato, J Hill, A K Ichikawa, A Ikeda, T Inagaki, T Ishida, T Ishii, M Ishitsuka, Y Itow, T Iwashita, H I Jang, J S Jang, E J Jeon, C K Jung, T Kajita, J Kameda, K Kaneyuki, I Kato, E Kearns, A Kibayashi, D Kielczewska, K Kobayashi, B J Kim, C O Kim, J Y Kim, S B Kim, T Kobayashi, M Kohama, Y Koshio, W R Kropp, J G Learned, S H Lim, I T Lim, H Maesaka, K Martens, T Maruyama, S Matsuno, C Mauger, C McGrew, S Mine, M Miura, K Miyano, S Moriyama, M Nakahata, K Nakamura, I Nakano, F Nakata, T Nakaya, S Nakayama, T Namba, K Nishikawa, S Nishiyama, S Noda, A Obayashi, A Okada, T Ooyabu, Y Oyama, M Y Pac, H Park, M Sakuda, N Sakurai, N Sasao, K Scholberg, E Sharkey, M Shiozawa, H So, H W Sobel, A Stachyra, J L Stone, Y Suga, L R Sulak, A Suzuki, Y Suzuki, Y Takeuchi, N Tamura, T Toshito, Y Totsuka, M R Vagins, C W Walter, R J Wilkes, S Yamada, S Yamamoto, C Yanagisawa, H Yokoyama, J Yoo, M Yoshida, J Zalipska

Affiliation

¹ Department of Physics, Seoul National University, Seoul 151-742, Korea.

PMID: 12570410
DOI: 10.1103/PhysRevLett.90.041801

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%.