Fukuda, Y; Ishihara, K; Itow, Y; Kajita, T; Kameda, J; Kasuga, S; Kobayashi, K; Kobayashi, Y; Koshio, Y; Miura, M; Nakahata, M; Nakayama, S; Obayashi, Y; Okada, A; Okumura, K; Sakurai, N; Shiozawa, M; Suzuki, Y; Takeuchi, H; Takeuchi, Y; Totsuka, Y; Yamada, S; Earl, M; Habig, A; Kearns, E; Messier, MD; Scholberg, K; Stone, JL; Sulak, LR; Walter, CW; Goldhaber, M; Barszczak, T; Casper, D; Gajewski, W; Kropp, WR; Mine, S; Price, LR; Smy, M; Sobel, HW; Vagins, MR; Ganezer, KS; Keig, WE et al., *Neutrino-induced upward stopping muons in Super-Kamiokande*,
Physics Letters B, vol. 467 no. 3-4
(1999),
pp. 185-193 .
**Abstract:**

*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. © 1999 Published by Elsevier Science B.V. All rights reserved.*