Neutrino-induced upward stopping muons in Super-Kamiokande

Y. Fukuda, K. Ishihara, Y. Itow, T. Kajita, J. Kameda, S. Kasuga, K. Kobayashi, Y. Kobayashi, Y. Koshio, M. Miura, M. Nakahata, S. Nakayama, Y. Obayashi, A. Okada, K. Okumura, N. Sakurai, M. Shiozawa, Y. Suzuki, H. Takeuchi, Y. TakeuchiY. Totsuka, S. Yamada, M. Earl, A. Habig, E. Kearns, M. D. Messier, K. Scholberg, J. L. Stone, L. R. Sulak, C. W. Walter, M. Goldhaber, T. Barszczak, D. Casper, W. Gajewski, W. R. Kropp, S. Mine, L. R. Price, M. Smy, H. W. Sobel, M. R. Vagins, K. S. Ganezer, W. E. Keig, R. W. Ellsworth, S. Tasaka, A. Kibayashi, J. G. Learned, S. Matsuno, V. J. Stenger, D. Takemori, T. Ishii, H. Ishino, T. Kobayashi, K. Nakamura, Y. Oyama, A. Sakai, M. Sakuda, O. Sasaki, S. Echigo, M. Kohama, A. T. Suzuki, T. Inagaki, K. Nishikawa, T. J. 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, M. Kirisawa, S. Inaba, K. Miyano, H. Okazawa, C. Saji, M. Takahashi, M. Takahata, K. Higuchi, Y. Nagashima, M. Takita, T. Yamaguchi, M. Yoshida, S. B. Kim, M. Etoh, A. Hasegawa, T. Hasegawa, S. Hatakeyama, K. Inoue, T. Iwamoto, M. Koga, T. Maruyama, H. Ogawa, J. Shirai, A. Suzuki, F. Tsushima, M. Koshiba, Y. Hatakeyama, M. Koike, M. Nemoto, K. Nishijima, H. Fujiyasu, T. Futagami, Y. Hayato, Y. Kanaya, K. Kaneyuki, Y. Watanabe, D. Kielczewska, J. S. George, A. L. Stachyra, R. J. Wilkes, K. K. Young

Research output: Contribution to journalArticlepeer-review

218 Scopus citations


A total of 137 upward stopping muons of minimum energy 1.6 GeV are observed by Super-Kamiokande during 516 detector live days. The measured muon flux is 0.39 ± 0.04(stat.) ± 0.02(syst.) × 10-13 cm-2s-1sr-1 compared to an expected flux of 0.73 ± 0.16(theo.) × 10-13 cm-2s-1sr-1. Using our previously-published measurement of the upward through-going muon flux, we calculate the stopping/through-going flux ratio ℛ, which has less theoretical uncertainty. The measured value of ℛ = 0.22 ± 0.02(stat.) ± 0.01(syst.) is significantly smaller than the value 0.37-0.04+0.05(theo.) expected using the best theoretical information (the probability that the measured ℛ is a statistical fluctuation below the expected value is 0.39%). A simultaneous fitting to zenith angle distributions of upward stopping and through-going muons gives a result which is consistent with the hypothesis of neutrino oscillations with the parameters sin22θ > 0.7 and 1.5 × 10-3 < Δm2 < 1.5 × 10-2 eV2 at 90% confidence level, providing a confirmation of the observation of neutrino oscillations by Super-Kamiokande using the contained atmospheric neutrino events.

Original languageEnglish (US)
Pages (from-to)185-193
Number of pages9
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Issue number3-4
StatePublished - 1999

Bibliographical note

Funding Information:
We gratefully acknowledge the cooperation of the Kamioka Mining and Smelting Company. The Super-Kamiokande experiment has been built and operated from funding by the Japanese Ministry of Education, Science, Sports and Culture, and the United States Department of Energy.


  • Atmospheric muon neutrinos
  • Cosmic rays
  • Neutrino oscillations
  • Super-Kamiokande
  • Upward stopping muons
  • Upward throughgoing muons


Dive into the research topics of 'Neutrino-induced upward stopping muons in Super-Kamiokande'. Together they form a unique fingerprint.

Cite this