[en] We have measured the decay rate for K/sub L/⁰ → μ⁺μ^- in a double-arm spectrometer at the Argonne zero-gradient synchrotron. Sixteen events were found, from which we calculate GAMMA (K/sub L/⁰ → μ⁺μ^-)/GAMMA (K/sub L/⁰ → π⁺π^-) = 4.2⁺¹/sup ./⁴/sub -/₀/sub ./₉ x 10^-6

[en] We have measured the branching ratio GAMMA (K/sub L/ → π⁺π^-)/GAMMA (K/sub L/ → all) to be (2.01 +- 0.09) x 10^-3. This value is in good agreement with other recent determinations of this branching ratio and yields a value for the CP-violating parameter eta/sub + -/ of (2.25 +- 0.05) x 10^-3

[en] The branching ratio GAMMA (K⁰/sub L/ → μ⁺μ^-)/GAMMA (K⁰/sub L/ → π⁺π^-) has been measured and found to be 4.0atsup +1.4atatsub -0.9at x 10^-6. With the same apparatus the branching ratio GAMMA (K⁰/sub L/ → π⁺π^-)/GAMMA (K⁰/sub L/ → all) has been measured to be (2.01 +- 0.09) x 10^-3. The combination of these two results gives GAMMA (K⁰/sub L/ → μ⁺μ^-)/GAMMA (K⁰/sub L/ → all) < 8.1atsup +2.8atatsub -1.8at x 10^-9. This result is consistent with the lower bound predicted from the decay rate K/sub L/ → γγ and unitarity

[en] Preliminary measurements of flux normalized charged current neutrino cross sections are presented. From a sample of 6000 neutrino events with energies between 50 and 260 GeV we find that sigmasub(ν)/Esub(ν) = (0.67 +- 0.04) x 10^-38cm²/GeV independent of neutrino energy. (orig.)

[en] We report on the observation of 12 like-sign ( μ^-μ^-) neutrino-induced dimuon events with muon momenta greater than 9 GeV. The background from π and K decay is 1.3 events so that we conclude that this prompt signal is real with a significance greater than 1 in 10⁷. Although the overall rate is higher than present theoretical estimates, the kinematic distributions of these events are qualitatively consistent with a picture of charm-anticharm production. The ratio of μ^-μ^-/μ^- shows a strong energy dependence and rises to (2.5 +- 1.0) x 10^-3 at E/sub ν/ = 250 GeV