166 research outputs found

    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)

    Search For 2nd-generation Leptoquarks In P(p)over-bar Collisions At Root-s=1.8 Tev

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    We present the results of a search for second generation leptoquarks S-2 using 19.3 pb(-1) of data collected at the Collider Detector at Fermilab (CDF) in p (p) over bar collisions at root s = 1.8 TeV during the 1992-93 collider run. We have searched for S-2 (S) over bar(2) pairs assuming that each leptoquark decays to a muon + quark with a branching ratio beta. We find two candidate events, consistent with an expected background of 1.11 +/- 0.48. We obtain upper limits on sigma(pp --> S-2 (S) over bar(2))beta(2) as a function of M(S2). Using a Monte Carlo prediction for S-2 (S) over bar(2) pair production, we exclude M(S2) < 131 GeV/c(2) for beta = 1 and M(S2) < 95 GeV/c(2) for beta = 0.5 at 95% C.L

    MEASUREMENT OF THE B-S MESON LIFETIME

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    The lifetime of the Bs meson is measured using the semileptonic decay Bs→Ds-+νX. The data sample consists of 19.3 pb-1 of pp̄ collisions at s=1.8 TeV collected by the Collider Detector at Fermilab during 1992-1993. There are 76±8 +Ds- signal events where the Ds is identified via the decay Ds-→φπ-, φ→K+K-. Using these events, the Bs meson lifetime is determined to be τs=1.42-0.23+0.27(stat)±0.11(syst) ps. A measurement of the Bs lifetime in a low statistics sample of exclusive Bs→J/ψ φ decays is also presented in this paper. © 1995 The American Physical Society

    Search for first generation leptoquark pair production in p(p)over-bar collisions at root s=1.8 TeV

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    We present the results of a search for first generation scalar leptoquarks pairs (S-1 (S)over-bar(1)) in 110 +/- 7 pb(-1) of data collected by the Collider Detector at Fermilab. We assume both leptoquarks decay to an electron and a quark. Three candidate events, with masses below 140 GeV/c(2) and consistent with background expectations, are observed. We obtain a 95% confidence level upper limit on the production cross section as a function of the leptoquark mass. Using a next-to-leading order calculation of S-1 (S)over-bar(1) production, we exclude scalar leptoquarks with mass less than 213 GeV/c(2) at 95% C.L. for a branching ratio into eq equal to 1

    Search for flavor-changing neutral current B meson decays in p(p)over-bar collisions at root s=1.8 TeV

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    We report on a search for the flavor-changing neutral current decays B d,s 0 → μ+μ-, B+ → μ+μ-K+ and B0 → μ+μ-K*0 using data from pp̄ collisions at √s = 1.8 TeV, collected with the Collider Detector at Fermilab during the 1992-1993 running period. We find no indication of such decays, and we set the following 90% confidence level upper limits on branching ratios: B(B0 → μ+μ-) < 1.6 × 10-6, B(BS 0 → μ+μ-) < 8.4 × 10-6, B(B+ → μ+μ-K+) < 1.0 × 10-5, and B(B0 → μ+μ-K*0) < 2.5 × 10-5

    UPSILON-PRODUCTION IN P(P)OVER-BAR COLLISIONS AT ROOT-S=1.8 TEV

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    We report on measurements of the Upsilon(1S), Upsilon(2S), and Upsilon(3S) differential, (d(2) sigma/dP(t)dy)(y=0), and integrated cross sections in p (p) over bar collisions at root s = 1.8 TeV using a sample of 16.6 +/- 0.6 pb(-1) collected by the Collider Detector at Fermilab. The three resonances were reconstructed through the decay Upsilon --> mu(+)mu(-). Comparison is made to a leading order QCD prediction

    Measurement of the γ + D*± cross section in p̄p collisions at √s = 1.8 TeV

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    We have measured the cross section of gamma + D-*+/- production in collisions at root s = 1.8 TeV using the Collider Detector at Fermilab. In this kinematic region, the Compton scattering process (g(c) --> gamma(c)) is expected to dominate and thus provide a direct link to the charm quark density in the proton. From the 45 +/- 18 gamma + D-*+/- candidates in a 16.4 pb(-1) data sample, we have determined the production cross section to be 0.38 +/- 0.15(stat) +/- 0.11(syst) nb for the rapidity range \y(D-*+/-)\ 6 GeV/c and 16 < p(T)(gamma) < 40 GeV/c. The measured cross section is compared to a theoretical prediction
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