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    85 research outputs found

    Measurement of the branching fraction B(Bu+→J/ψπ+) and search for Bc+→J/ψπ+

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    We report on a measured of the branching fraction of the Cabibbo-suppressed decay B-u(+)-->J/psi pi(+), where J/psi-->mu(+)mu(-). The data were collected by the Collider Detector at Fermilab during 1992-1995 and correspond to an integrated luminosity of 110 pb(-1) in (p) over tildep$ collisions at root s=1.8 TeV. A signal of 28(-9)(+10) events is observed and we demonstrate the ratio of branching fractions B(B-u(+)-->J/psi pi)/B(B-u(+)-->J/psi K+) to be [5.0(-1.7)(+1.9) (stat)+/-0.1(syst)]%. Using the world average value for B(B-u(+)-->J/psi K+), we calculate the branching fraction B(B-u(+)-->J/psi pi(+)) to be (5.0(-1.9)(+2.1))x10(-5). We also search for the decay B-c(+)-->J/psi pi(+) and report a 95% confidence level limit on sigma(B-c(+))B(B-c(+)-->J/psi pi(+)/sigma(B-u(+))B(B-u(+)-->J/psi K+) as a function of the B-c(+) lifetime
    Università degli Studi del Molise: IRIS
    Archivio della Ricerca - Università degli Studi di Siena
    Archivio istituzionale della ricerca - Università degli Studi di Udine
    Archivio Istituzionale della Ricerca - Università degli Studi di Pavia
    Archivio della Ricerca - Università di Pisa
    Archivio istituzionale della ricerca - Università di Genova
    Archivio istituzionale della ricerca - Università di Padova

    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)
    Università degli Studi del Molise: IRIS
    Crossref
    Archivio della Ricerca - Università degli Studi di Siena
    Archivio della Ricerca - Università di Pisa
    Archivio istituzionale della ricerca - Università di Genova
    Archivio istituzionale della ricerca - Università di Padova

    MEASUREMENT OF THE POLARIZATION IN THE DECAYS B-D-]J/PSI-K-(ASTERISK-0) AND BS-]J/PSI-PHI

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    This Letter reports on measurements of the longitudinal polarization fractions in the decays B-d --> J/psi K*(0) and B-s --> J/psi phi using data collected with the Collider Detector at Fermilab. B-d mesons are reconstructed through the decay chain B-d --> J/psi K*(0), J/psi --> mu(+)mu(-), K*(0) --> K(+)phi(-). A sample of 65 +/- 10 B-d events is used to obtain a longitudinal polarization fraction of T-L/Gamma = 0.65 +/- 0.10(stat) +/- 0.04(syst). B-s mesons are reconstructed through the decay chain B-s --> J/psi phi, J/psi --> mu(+)mu(-), phi --> K+K-. A sample of 19 +/- 5 B-s events is used to obtain the result Gamma(L)/Gamma = 0.56 +/- 0.21(stat)-(+0.02)(0.04)(syst)
    Università degli Studi del Molise: IRIS
    Archivio della Ricerca - Università degli Studi di Siena
    Archivio della Ricerca - Università di Pisa
    Oxford University Research Archive
    Archivio istituzionale della ricerca - Università di Genova
    Archivio istituzionale della ricerca - Università di Padova

    Ratios of bottom meson branching fractions involving J/psi mesons and determination of b quark fragmentation fractions

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    We report a measurement of the ratios of the decay rates of the B+, B0, and Bs 0 mesons into exclusive final states containing a J/ψ meson. The final states were selected from 19.6 pb-1 of pp̄ collisions recorded by the Collider Detector at Fermilab. These data are interpreted to determine the b quark fragmentation fractions fu, fd, and fs. We also determine the branching fractions for the decay modes B+ → J/ψK+, B+ → J/ψK*(892)+, B0 → J/ψK0, B0 → J/ψK*(892)0, and Bs 0 → J/ψφ(1020). We discuss the implications of these measurements to B meson decay models. © 1996 The American Physical Society
    Università degli Studi del Molise: IRIS
    Archivio della Ricerca - Università degli Studi di Siena
    Archivio istituzionale della ricerca - Università degli Studi di Udine
    Archivio Istituzionale della Ricerca - Università degli Studi di Pavia
    Archivio della Ricerca - Università di Pisa
    Oxford University Research Archive
    Archivio istituzionale della ricerca - Università di Genova
    Archivio istituzionale della ricerca - Università di Padova

    Observation of Lambda(b)(0)->J/psi Lambda at the Fermilab proton-antiproton collider

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    The decay Lambda(b)(0) --> J/psi Lambda is observed in 110 pb(-1) of p (p) over bar collisions taken at root s = 1.8 TeV. These data are used to measure a Lambda(b)(0) mass of 5621+/-4(stat)+/-3(syst) MeV/c(2), and a mass difference between the Lambda(b)(0) and the B-0 of 340+/-5(stat)+/-1(syst) MeV/c(2). The production cross-section times branching fraction for the decay Lambda(b)(0) --> J/psi Lambda relative to that for the decay B-0 --> J/psi K-S(0) has been measured to be 0.27+/-0.12(stat)+/-0.05(syst)
    Università degli Studi del Molise: IRIS
    Archivio Istituzionale della Ricerca - Università degli Studi di Pavia
    Oxford University Research Archive
    Archivio istituzionale della ricerca - Università di Genova
    Archivio istituzionale della ricerca - Università di Padova

    Production of J/psi mesons from chi(c) meson decays in p(p)over-bar collisions at root s=1.8 TeV

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    We have measured the fraction of J/psi mesons originating from chi(c) meson decays in p (p) over bar collisions at root s = 1.8 TeV. The fraction, for P-T/(J/psi) > 4.0 GeV/c and \(eta) over dot(J/psi) < 0.6, not including contributions from b flavored hadrons, is 29.7% +/- 1.7%(stat) +/- 5.7%(syst). We have determined the cross sections for J/psi mesons originating from chi(c) decays and for directly produced J/psi mesons. We have found that direct J/psi production is in excess of the prediction of the color singlet model by the same factor found for direct psi(2S) production
    Università degli Studi del Molise: IRIS
    Crossref
    Archivio della Ricerca - Università degli Studi di Siena
    Archivio Istituzionale della Ricerca - Università degli Studi di Pavia
    Archivio della Ricerca - Università di Pisa
    Oxford University Research Archive
    Archivio istituzionale della ricerca - Università di Padova

    J/psi and psi(2S) production in p(p)over-bar collisions at root s=1.8 TeV

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    We present a study of J/psi and psi(2S) production in p (p) over bar collisions, at root s = 1.8 TeV with the CDF detector at Fermilab. The J/psi and psi(2S) mesons are reconstructed using their mu(+)mu(-) decay modes. We have measured the inclusive production cross section for both mesons as a function of their transverse momentum in the central region, \eta\ < 0.6. We also measure the fraction of these events originating from b hadrons. We thus extract individual cross-sections for J/psi and psi(2S) mesons from b-quark decays and prompt production. We find a large excess (approximately a factor of 50) of direct psi(2S) production compared with predictions from the color singlet model
    Università degli Studi del Molise: IRIS
    Crossref
    Archivio della Ricerca - Università degli Studi di Siena
    Archivio Istituzionale della Ricerca - Università degli Studi di Pavia
    Archivio della Ricerca - Università di Pisa
    Oxford University Research Archive
    Archivio istituzionale della ricerca - Università di Padova

    Measurement of the lifetime of the Bs0 meson using the exclusive decay mode Bs0 → J/ψ φ

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    The lifetime of the B0s meson is measured using the exclusive decay mode B0s→J/ψφ, where J/ψ→μ+μ− and φ→K+K−. The data sample consists of 110pb−1 of pp ̄ collisions at √s=1.8TeV, collected by the CDF detector at the Fermilab Tevatron collider during 1992–1995. We find 58±12 signal events, and the B0s meson lifetime is determined to be τB0s=1.34+0.23−0.19(stat)±0.05(syst) ps. This result is consistent with previous measurements of the B0s, B+, and B0d meson lifetimes and with theoretical predictions
    Università degli Studi del Molise: IRIS
    Crossref
    Archivio della Ricerca - Università degli Studi di Siena
    Archivio istituzionale della ricerca - Università degli Studi di Udine
    Archivio Istituzionale della Ricerca - Università degli Studi di Pavia
    Archivio della Ricerca - Università di Pisa
    Archivio istituzionale della ricerca - Università di Genova
    Archivio istituzionale della ricerca - Università di Padova

    Measurement of B hadron lifetimes using J/psi final states at CDF

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    The average bottom-hadron and individual B+, B0, and Bs0 meson lifetimes have been determined using decays with a J/ψ→μ+μ- in the final state. The data sample consists of 110 pb-1 of p̄p collisions at √s =1.8 TeV collected by the CDF detector at the Fermilab Tevatron collider during 1992-1995. For the average lifetime of B hadrons decaying into J/ψ+X, we obtain =1.533±0.015(stat)-0.031+0.035(syst) ps. For the B+ and B0 meson lifetimes, we determine τ(B+)=1.68±0.07(stat) ±0.02(syst) ps, τ(B0)=1.58 ±0.09(stat) ±0.02(syst) ps, and τ(B+)/τ(B0)=1.06±0.07(stat) ±0.02(syst). For the Bs0 meson lifetime, we find τ(Bs0)=1.34-0.19+0.23(stat) ±0.05(syst) ps
    Università degli Studi del Molise: IRIS
    Archivio della Ricerca - Università degli Studi di Siena
    Archivio Istituzionale della Ricerca - Università degli Studi di Pavia
    Archivio della Ricerca - Università di Pisa
    Oxford University Research Archive
    Archivio istituzionale della ricerca - Università di Padova

    Measurement of the mass of the B-s(0) meson

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    We measure the mass of the B-s(0) meson by reconstructing the decay chain B-s(0)-->J/psi phi, J/psi-->mu(+)mu(-), and phi-->K+K-. The data are obtained from 19.3 pb(-1) of integrated luminosity of collisions at root s=1.8 TeV using the Collider Detector at Fermilab. A sample of 80 000 inclusive J/psi-->mu(+)mu(-) events is used to study systematic biases in track reconstruction and to calibrate the momentum scale. We reconstruct the kinematically similar decays B+-->J/mu K+ and B-0-->J/psi K*(0) to study the mass measurement technique used for the B-s(0) meson. Based on the observation of 32 +/- 6 candidates, the mass of the B-s(0) meson is measured to be 5369.9 +/- 2.3 +/- 1.3 MeV/c(2) and the mass difference between B-s(0) and the average mass of B+ and B-0 is determined to be 89.7 +/- 2.7 +/- 1.2 MeV/c(2)
    Crossref
    Archivio della Ricerca - Università degli Studi di Siena
    Archivio della Ricerca - Università di Pisa
    Oxford University Research Archive
    Archivio istituzionale della ricerca - Università di Genova
    Archivio istituzionale della ricerca - Università di Padova
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