40 research outputs found

    Drell-Yan and Upsilon production in UA1

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    Measurement of B(b)over-bar Correlations At the Cern P(p)over-bar Collider

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    We report on measurements of correlated bbBAR production in ppBAR collisions at square-root s = 630 GeV, using dimuon data to tag both the b and bBAR quarks. Starting from an inclusive dimuon sample we obtain improved cross-sections for single inclusive beauty production and confirm our earlier results on B0-B0BAR mixing. From a study of bbBAR correlations we derive explicit cross-sections for semi-differential bbBAR production. We compare the measured cross-sections and correlations to O(alpha(s)3) QCD predictions and find good quantitative agreement. From the measured angular distributions we establish a sizeable contribution from higher order QCD processes with a significance of about seven standard deviations. A large nonperturbative contribution to these higher order corrections is excluded

    Measurement of alpha-s from b anti-b production at the CERN p anti-p collider

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    The UA1 Collaboration has recently improved its measurement of the beauty production cross-section by including explicit measurements of correlations. Using these data we have determined the strong coupling constant alpha(s). The comparison of the measured cross-section for 2-body final states with O(alpha(s)(3)) QCD predictions yields a measurement of alpha(S)(20 GeV) = 0.145(-0.010exp-0.016 th)(+0.012+0.013), corresponding to alpha(S)(M(Z)) = 0.113(-0.006 exp-0.009 th)(+0.007+0.008). This is the first theoretically well-defined measurement of alpha(S) from a purely hadronic production process. Evaluating alpha(S) from cross-sections at different Q(2)-values we find that the running of alpha(S) is needed for internal consistency of the UA1 data

    Measurement of B0 - anti-B0 mixing at the CERN S p anti-p S collider

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    We report on a new measurement of B0-BBAR0 mixing at the CERN SppBARS Collider. Mixing is measured in the non-isolated high mass dimuon sample using data from the 1988-1989 collider runs. The measured value of the mixing parameter, chi, is 0.145 +/- 0.035(stat.) +/- 0.014(syst.). The average of this measurement and that from our 1984-1985 data is chi = 0.148 +/- 0.029(stat.) +/- 0.017(syst.) assuming fully correlated systematic errors. Using the measurement of chi-d from ARGUS and CLEO, we obtain chi-s = 0.50 +/- 0.20, which gives a limit of chi-s > 0.17 (0.12) at 90% (95%) CL. Including the measurements of chi from the ALEPH and L3 experiments gives chi-s = 0.53 +/- 0.15, and a limit of chi-s > 0.27 (0.23) at 90% (95%) CL

    COMPARISON OF W AND DIRECT PHOTON CROSS-SECTIONS AT LARGE TRANSVERSE MOMENTA

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    A search for rare B meson decays at the CERN S p anti-p S collider

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    We report on a search for the decays B0 --> mu+mu-, B --> mu+mu-X and B(d)0 --> mu+mu-K0*, which are expected to be rare if mediated by flavor changing neutral currents. Using data collected during the 1984-1989 CERN ppBAR Collider runs, the UA1 search was carried out using mu+mu- events with 3.9 mu+mu- of 8.3 x 10(-6), for B --> mu+mu-X of 5.0 x 10(-5), and for B(d)0 --> mu+mu-K0* of 2.3 x 10(-5). Implications for upper limits on the t-quark mass are discussed

    Measurement of the ratio RσWR \equiv \sigma_{W}Br(W μν\to \mu\nu)/ σZ\sigma_{Z}Br(Z \to μμ\mu\mu) and ΓWtot\Gamma^{tot}_{W} at the CERN proton-antiproton collider

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    Beauty production at the CERN pp\overline{p} collider ; Revised version

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