16 research outputs found

    HFAG Charm Mixing Averages

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    Recently the first evidence for charm mixing has been reported by several experiments. To provide averages of these mixing results and other charm results, a new subgroup of the Heavy Flavor Averaging Group has been formed. We here report on the method and results of averaging the charm mixing results

    Charm and Charmonium Spectroscopy

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    Recent experimental results in charm and charmonium spectroscopy are reviewed.Comment: 4 pages, contributed to the Proceedings of BEACH 2006, Lancater, Englan

    Measurement of the J/Psi Production Cross Section in 920 GeV/c Fixed-Target Proton-Nucleus Interactions

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    The mid-rapidity (dsigma_(pN)/dy at y=0) and total sigma_(pN) production cross sections of J/Psi mesons are measured in proton-nucleus interactions. Data collected by the HERA-B experiment in interactions of 920 GeV/c protons with carbon, titanium and tungsten targets are used for this analysis. The J/Psi mesons are reconstructed by their decay into lepton pairs. The total production cross section obtained is sigma_(pN)(J/Psi) = 663 +- 74 +- 46 nb/nucleon. In addition, our result is compared with previous measurements

    Kinematic distributions and nuclear effects of J/psi production in 920-GeV fixed-target proton-nucleus collisions

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    Measurements of the kinematic distributions of J/ψJ/\psi mesons produced in pp-C, pp-Ti and pp-W collisions at s=41.6GeV\sqrt{s}=41.6 \mathrm{GeV} in the Feynman-xx region 0.34<xF<0.14-0.34 < x_{F} < 0.14 and for transverse momentum up to pT=5.4GeV/cp_T = 5.4 \mathrm{GeV}/c are presented. The xFx_F and pTp_T dependencies of the nuclear suppression parameter, α\alpha, are also given. The results are based on 2.41052.4 \cdot 10^{5} J/ψJ/\psi mesons in both the e+ee^+ e^- and μ+μ\mu^{+}\mu^{-} decay channels. The data have been collected by the HERA-B experiment at the HERA proton ring of the DESY laboratory. The measurement explores the negative region of xFx_{F} for the first time. The average value of α\alpha in the measured xFx_{F} region is 0.981±0.0150.981 \pm 0.015. The data suggest that the strong nuclear suppression of J/ψJ/\psi production previously observed at high xFx_F turns into an enhancement at negative xFx_F
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