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 n m $ n t oscillations with sin 2 2u . Atmospheric neutrinos are produced as decay products in hadronic showers resulting from collisions of cosmic rays with nuclei in the upper atmosphere. Production of electron and muon neutrinos is dominated by the processes p 1 ! m 1 1 n m followed by m 1 ! e 1 1 n m 1 n e (and their charge conjugates) giving an expected ratio 1562 0031-9007͞98͞81(8)͞1562(6)$15.00
We report the observation of a narrow charmoniumlike state produced in the exclusive decay process B+/--->K+/-pi(+)pi(-)J/psi. This state, which decays into pi(+)pi(-)J/psi, has a mass of 3872.0+/-0.6(stat)+/-0.5(syst) MeV, a value that is very near the M(D0)+M(D(*0)) mass threshold. The results are based on an analysis of 152M B-Bmacr; events collected at the Upsilon(4S) resonance in the Belle detector at the KEKB collider. The signal has a statistical significance that is in excess of 10sigma.
A total of 614 upward through-going muons of minimum energy 1.6 GeV are observed by Super-Kamiokande during 537 detector live days. The measured muon flux is (1.74 ± 0.07(stat.) ± 0.02(sys.)) × 10 −13 cm −2 s −1 sr −1 compared to an expected flux of (1.97 ± 0.44(theo.)) × 10 −13 cm −2 s −1 sr −1 . The absolute measured flux is in agreement with the prediction within the errors. However, the zenith angle dependence of the observed upward through-going muon flux does not agree with no-oscillation predictions. The observed distortion in shape is consistent with the νµ ↔ ντ oscillation hypothesis with sin 2 2θ > 0.4 and 1 × 10 −3 < ∆m 2 < 1 × 10 −1 eV 2 at 90 % confidence level.
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