485 research outputs found

    Light Quark Resonances in pbar p Annihilations at 5.2 GeV/c

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    Data from the Fermilab E835 experiment have been used to study the reaction pbar p -> eta eta pi0 at 5.2 GeV/c. A sample of 22 million six photons events has been analyzed to construct the Dalitz plot containing ~80k eta eta pi0 events. A partial wave analysis of the data has been done. Six f_J-states decaying into eta eta and five a_J-states decaying into eta pi0 are identified in the mass region ~1.3 and 2.4 GeV, and their masses, widths and spins are determined by maximum likelihood analysis of the data. Two f_0 states are identified with the popular candidates for the lightest scalar glueball, f_0(1500) and f_0(1710).Comment: 7 pages, 6 figure

    Search for X(3872) in gamma gamma Fusion and ISR at CLEO

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    We report on a search for the X(3872) state using 15.1 fb^{-1} of e+ e- annihilation data taken with the CLEO III detector in the sqrt{s} = 9.46-11.30 GeV region. Separate searches for the production of X(3872) in untagged gamma gamma fusion and e+ e- annihilation following initial state radiation are made by taking advantage of the unique correlation of J/psi -> l+ l- in X(3872) decay into J/psi pi+ pi-. No signals are observed in either case, and 90% confidence upper limits are established as (2J+1)Gamma_{gammagamma}(X(3872))B(X -> J/psi pi+ pi-) J/psi pi+ pi-) < 8.3 eV.Comment: 4 pages, 2 figures, to appear in the proceedings of the 1st Meeting of the APS Topical Group on Hadronic Physics, Fermilab, Oct. 24-26, 200

    Charm Leptonic and Semileptonic Decays

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    Experimental results for the pseudoscalar decay constants f_{D} and f_{D_s} are reviewed. Semileptonic form factor results from D -> (pseudoscalar) l nu and D -> (vector) l nu decays are also reviewed.Comment: 8 pages, 4 figures, presented at the 11th International Conference on B-Physics at Hadron Machines (BEAUTY 2006) Sept. 25-29, Oxford, England; corrected typo

    New Results From CLEO and BES

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    Latest experimental results from BES in the charmonium mass region, and those from CLEO in the bottomonium and charmonium spectroscopy are reviewed.Comment: 12 pages, 12 figures, Presented at First Meeting of the APS Topical Group on Hadron Physics, Fermilab, Batavia, Illinois, Oct 24-26, 200

    Interference Study of the chi_c0 (1^3P_0) in the Reaction Proton-Antiproton -> pi^0 pi^0

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    Fermilab experiment E835 has observed proton-antiproton annihilation production of the charmonium state chi_c0 and its subsequent decay into pi^0 pi^0. Although the resonant amplitude is an order of magnitude smaller than that of the non-resonant continuum production of pi^0 pi^0, an enhanced interference signal is evident. A partial wave expansion is used to extract physics parameters. The amplitudes J=0 and 2, of comparable strength, dominate the expansion. Both are accessed by L=1 in the entrance proton-antiproton channel. The product of the input and output branching fractions is determined to be B(pbar p -> chi_c0) x B(chi_c0 -> pi^0 pi^0)= (5.09 +- 0.81 +- 0.25) x 10^-7.Comment: 4 pages, 4 figures, Accepted by PRL (July 2003

    Precision measurements of the total and partial widths of the psi(2S) charmonium meson with a new complementary-scan technique in antiproton-proton annihilations

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    We present new precision measurements of the psi(2S) total and partial widths from excitation curves obtained in antiproton-proton annihilations by Fermilab experiment E835 at the Antiproton Accumulator in the year 2000. A new technique of complementary scans was developed to study narrow resonances with stochastically cooled antiproton beams. The technique relies on precise revolution-frequency and orbit-length measurements, while making the analysis of the excitation curve almost independent of machine lattice parameters. We study the psi(2S) meson through the processes pbar p -> e+ e- and pbar p -> J/psi + X -> e+ e- + X. We measure the width to be Gamma = 290 +- 25(sta) +- 4(sys) keV and the combination of partial widths Gamma_e+e- * Gamma_pbarp / Gamma = 579 +- 38(sta) +- 36(sys) meV, which represent the most precise measurements to date.Comment: 17 pages, 3 figures, 3 tables. Final manuscript accepted for publication in Phys. Lett. B. Parts of the text slightly expanded or rearranged; results are unchange

    Measuring V_ub and probing SUSY with double ratios of purely leptonic decays of B and D mesons

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    The experimental prospects for precise measurements of the leptonic decays B_u -> tau nu / mu nu, B_s -> mu+ mu-, D -> mu nu and D_s -> mu nu / tau nu are very promising. Double ratios involving four of these decays can be defined in which the dependence on the values of the decay constants is essentially eliminated, thus enabling complementary measurements of the CKM matrix element V_ub with a small theoretical error. We quantify the experimental error in a possible future measurement of |V_ub| using this approach, and show that it is competitive with the anticipated precision from the conventional approaches. Moreover, it is shown that such double ratios can be more effective than the individual leptonic decays as a probe of the parameter space of supersymmetric models. We emphasize that the double ratios have the advantage of using |V_ub| as an input parameter (for which there is experimental information), while the individual decays have an uncertainty from the decay constants (e.g. f_B_s), and hence a reliance on theoretical techniques such as lattice QCD.Comment: 21 pages, 4 figure

    Search for rare and forbidden decays of charm and charmed-strange mesons to final states h^+- e^-+ e^+

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    We have searched for flavor-changing neutral current decays and lepton-number-violating decays of D^+ and D^+_s mesons to final states of the form h^+- e^-+ e^+, where h is either \pi or K. We use the complete samples of CLEO-c open-charm data, corresponding to integrated luminosities of 818 pb^-1 at the center-of-mass energy E_CM = 3.774 GeV containing 2.4 x 10^6 D^+D^- pairs and 602 pb^-1 at E_CM = 4.170 GeV containing 0.6 x 10^6 D^*+-_s D^-+_s pairs. No signal is observed in any channel, and we obtain 90% confidence level upper limits on branching fractions B(D^+ --> \pi^+ e^+ e^-) < 5.9 x 10^-6, B(D^+ --> \pi^- e^+ e^+) K^+ e^+ e^-) < 3.0 x 10^-6, B(D^+ --> K^- e^+ e^+) \pi^+ e^+ e^-) < 2.2 x 10^-5, B(D^+_s --> \pi^- e^+ e^+) K^+ e^+ e^-) < 5.2 x 10^-5, and B(D^+_s --> K^- e^+ e^+) < 1.7 x 10^-5.Comment: 9 pages, available through http://www.lns.cornell.edu/public/CLNS

    Theoretical Overview: The New Mesons

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    After commenting on the state of contemporary hadronic physics and spectroscopy, I highlight four areas where the action is: searching for the relevant degrees of freedom, mesons with beauty and charm, chiral symmetry and the D_{sJ} levels, and X(3872) and the lost tribes of charmonium.Comment: 10 pages, uses jpconf.cls; talk at First Meeting of the APS Topical Group on Hadronic Physic
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