29 research outputs found

    Light Spectrum and Decay Constants in Full QCD with Wilson Fermions

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    We present results from an analysis of the light spectrum and the decay constants f_{\pi} and f_V^{-1} in Full QCD with n_f=2 Wilson fermions at a coupling of beta=5.6 on a 16^3x32 lattice.Comment: 3 pages, LaTeX with 4 eps figures, Talk presented at LATTICE96(spectrum

    Survey-Sami and Indigenous Research

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    Centre for Sami Studies at The University of Tromsø has by The Research Council of Norway been assigned to make a survey of Sami and Indigenous research going on in the Nordic countries

    Transverse Structure of Nucleon Parton Distributions from Lattice QCD

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    This work presents the first calculation in lattice QCD of three moments of spin-averaged and spin-polarized generalized parton distributions in the proton. It is shown that the slope of the associated generalized form factors decreases significantly as the moment increases, indicating that the transverse size of the light-cone quark distribution decreases as the momentum fraction of the struck parton increases.Comment: 4 pages, 1 figur

    Calculation of Nucleon Electromagnetic Form Factors

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    The fomalism is developed to express nucleon matrix elements of the electromagnetic current in terms of form factors consistent with the translational, rotational, and parity symmetries of a cubic lattice. We calculate the number of these form factors and show how appropriate linear combinations approach the continuum limit.Comment: Lattice 2002 (hadronic matrix elements) 3 page

    An Estimate of alpha_S from Bottomonium in Unquenched QCD

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    We estimate the strong coupling constant from the perturbative expansion of the plaquette. The scale is set by the 2S-1S and 1P-1S splittings in bottomonium which are computed in NRQCD on dynamical gauge configurations with nf=2 degenerate Wilson quarks at intermediate masses. We have increased the statistics of our spectrum calculation in order to reliably extrapolate in the sea-quark mass. We find a value of alpha_MS(m_Z) = 0.1118(26) which is somewhat lower than previous estimates within NRQCD.Comment: LATTICE98(heavyqk

    Light Quark Physics with Dynamical Wilson Fermions

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    We present results for spectroscopy, quark masses and decay constants obtained from SESAM's and TkL's large statistics simulations of QCD with two dynamical Wilson fermions.Comment: 3 pages; to appear in the proceedings of Lat.'9

    Masses of singlet and non-singlet 0++ particles

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    We compute the mass of the singlet 0++ state using both (psi_bar psi) and Wilson loop operators from a N_f=2 lattice QCD calculation.Comment: Lattice2002(spectrum

    Unquenching the Quark Model and Screened Potentials

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    The low-lying spectrum of the quark model is shown to be robust under the effects of `unquenching'. In contrast, the use of screened potentials is shown to be of limited use in models of hadrons. Applications to unquenching the lattice Wilson loop potential and to glueball mixing in the adiabatic hybrid spectrum are also presented.Comment: 6 pages, 3 ps figures, revtex. Version to appear in J. Phys.

    Glueballs and string breaking from full QCD

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    We present results on the static potential, and torelon and glueball masses from simulations of QCD with two flavours of dynamical Wilson fermions on 163×3216^3\times 32 and 243×4024^3\times 40 lattices at β=5.6\beta=5.6.Comment: Talk presented by Gunnar Bali at International Symposium on Lattice Field Theories (Lattice 97), Edinburgh, July 1997, 3 pages LaTeX (epscrc2.sty) with 4 eps figure

    Preliminary Calculation of αs\alpha_s from Green Functions with Dynamical Quarks

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    We present preliminary results on the computation of the QCD running coupling constant in the MOM~\widetilde{MOM} scheme and Landau gauge with two flavours of dynamical Wilson quarks. Gluon momenta range up to about 7 GeV (β=\beta = 5.6, 5.8 and 6.0) with a constant dynamical-quark mass. This range already allows to exhibit some evidence for a sizable 1/μ21/\mu^2 correction to the asymptotic behaviour, as in the quenched approximation, although a fit without power corrections is still possible with a reasonable χ2\chi^2. Following the conclusions of our quenched study, we take into account 1/μ21/\mu^2 correction to the asymptotic behaviour. We find ΛMSˉNf=2=264(27)MeV×[a1(5.6,0.1560)/2.19GeV]\Lambda_{\rm \bar{MS}}^{N_f=2} = 264(27) {\rm MeV} \times [{a^{-1}(5.6,0.1560)}/{2.19 {\rm GeV}}] , which leads to αs(MZ)=0.113(3)(4)\alpha_s(M_Z) = 0.113(3)(4). The latter result has to be taken as a preliminary indication rather than a real prediction in view of the systematic errors still to be controlled. Still, being two sigmas below the experimental result makes it very encouraging.Comment: 14 pages, 3 figs., 2 tabs., revte
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