1,479 research outputs found

    Jets from UA1

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    Reconstruction of B-0->J/psi K-S(0) and measurement of ratios of branching ratios involving B->J/psi K* and B+->J/psi K+

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    We report on the reconstruction of the decay mode B-0 --> J/psi K-S(0) using 19.3 pb(-1) of data collected by the Collider Detector at Fermilab in collisions at root s = 1.8 TeV. A signal of 41.8 +/- 6.9 events, with a signal-to-background ratio of 9:1, is observed. Three additional decay modes B+ --> J/psi K+, B-0 --> J/psi K*(892)(0), and B+ --> J/psi K*(892)(+) are reconstructed. We measure three ratios of branching ratios, each one relative to the B+ --> J/psi K+ mode. We also report the ratio of decay rates, Gamma(B --> J/psi K*)/Gamma(B --> J/psi K), for the vector-vector relative to the vector-pseudoscalar modes, to be 1.32 +/- 0.23(stat) +/- 0.16(syst)

    Measurement of partial widths and search for direct CP violation in D-0 meson decays to K-K+ and pi(-)pi(+)

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    We present a measurement of relative partial widths and decay rate CP asymmetries in K-K+ and pi(-)pi(+) decays of D-0 mesons produced in p(p) over bar collisions at root s = 1.96 TeV. We use a sample of 2x10(5) D*+-> D-0 pi(+) (and charge conjugate) decays with the D-0 decaying to K-pi(+), K-K+, and pi(-)pi(+), corresponding to 123 pb(-1) of data collected by the Collider Detector at Fermilab II experiment at the Fermilab Tevatron collider. No significant direct CP violation is observed. We measure Gamma(D-0 -> K-K+)/Gamma(D-0 -> K-pi(+)) = 0.0992 +/- 0.0011 +/- 0.0012, Gamma(D-0 ->pi(-)pi(+))/Gamma(D-0 -> K-pi(+)) = 0.035 94 +/- 0.000 54 +/- 0.000 40, A(CP)(K-K+) = (2.0 +/- 1.2 +/- 0.6)%, and A(CP)(pi(-)pi(+)) = (1.0 +/- 1.3 +/- 0.6)%, where, in all cases, the first uncertainty is statistical and the second is systematic

    Observation of B+->Psi(2S)K+ and B-0 ->Psi(2S)K*(892)(0) decays and measurements of B-meson branching fractions into J/Psi and Psi(2S) final states

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    We report the observations of the decays beta(+) --> psi(2S)K+ and B-0 --> psi(2S)K*(892)(0) in collisions at a center-of-mass energy of 1.8 TeV using a 110 pb(-1) data sample recorded by the Collider Detector at Fermilab. We also reconstruct the decays B+ --> J/psi K+ and B-0 --> J/psi K*(892)(0) and measure the six ratios of branching fractions of these four decays. The relative branching-fraction results are shown to be consistent with phenomenological factorization calculations of hadronic B-meson decays. We use the world-average branching fraction B(B+ --> J/psi K+) to derive B(B+ --> psi(2S)K+) = (0.56+/-0.08+/-0.10) X 10(-3), B(B-0 --> psi(2s)K*(892)(0)) = (0.92+/-0.20+/-0.16) X 10(-3), and B(B-0 --> J/psi K*(892)(0)) = (1.78+/-0.14+/-0.29) x 10(-3), where the first and second uncertainties are statistical and systematic, respectively. [S0556-2821(98)05117-0

    Search for the flavor-changing neutral current decays B+ -> mu(+)mu K--(+) and B-0 -> mu(+)mu K--(*0)

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    We report on a search for the flavor-changing neutral current decays B+-->mu(+)mu(-)K(+) and B-0 --> mu(+)mu(-) K-*0 using 88 pb(-1) of data from (p) over bar p collisions at root s = 1.8 TeV, collected with the Collider Detector at Fermilab. Finding no evidence for these decays, we set upper limits on the branching fractions B(B+ -->mu(+)mu(-)K(+)) mu(+) mu(-) K-*0) < 4.0 x 10(-6) at the 90% confidence level

    Measurement of the ratio of branching fractions B(D0→K +π -)/B(D0→K -π +) using the CDF II detector

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    We present a measurement of R B , the ratio of the branching fraction for the rare decay D 0 → K + π − to that for the Cabibbo-favored decay D 0 → K − π + . Charge-conjugate decays are implicitly included. A signal of 2005 ± 104 events for the decay D 0 → K + π − is obtained using the CDF II detector at the Fermilab Tevatron collider. The data set corresponds to an integrated luminosity of 0.35     fb − 1 produced in ¯ p p collisions at √ s = 1.96     TeV . Assuming no mixing, we find R B = [ 4.05 ± 0.21 ( stat ) ± 0.11 ( syst ) ] × 10 − 3 . This measurement is consistent with the world average, and comparable in accuracy with the best measurements from other experiments
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