634 research outputs found

    Tuning the Tadpole Improved Clover Wilson Action on Coarse Anisotropic Lattices

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    Wilson quark action, with tadpole improved clover term added, is studied on coarse anisotropic lattices. The bare velocity of light parameter in this action is determined non-perturbatively using the pseudo-scalar and vector meson dispersion relations for various values of the gauge coupling ÎČ\beta and bare quark mass parameter Îș\kappa.Comment: 7 pages LateX, typeset with elsart.cls, 1 figure, 5 tables (4 more tables added), 2 references adde

    Scale Setting for αs\alpha_s Beyond Leading Order

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    We present a general procedure for applying the scale-setting prescription of Brodsky, Lepage and Mackenzie to higher orders in the strong coupling constant \alphas. In particular, we show how to apply this prescription when the leading coefficient or coefficients in a series in \alphas are anomalously small. We give a general method for computing an optimum scale numerically, within dimensional regularization, and in cases when the coefficients of a series are known. We find significant corrections to the scales for Re+e−R_{e^+ e^-}, Γ(B→XueΜˉ)\Gamma(B \to X_u e \bar{\nu}), Γ(t→bW)\Gamma(t \to b W), and the ratios of the quark pole to \MSbar and lattice bare masses.Comment: Lattice 2000 (Perturbation Theory), 5 pages, 7 figures, LaTe

    Excitations of torelon

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    The excitations of gluonic flux tube in a periodic lattice are examined. Monte Carlo simulations from an anisotropic lattice are presented and the comparison with effective string models is discussed.Comment: Talk at Lattice 2003; 3 pages, 4 figure

    The First Calculation for the Mass of the Ground 4++4^{++} Glueball State on Lattice

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    Under the quenched approximation, we perform a lattice calculation for the mass of the ground 4++4^{++} glueball state in E++E^{++} channel on a D=3+1D=3+1 lattice. Our calculation shows that the mass of this state is MG(4++)=3.65(6)(18)GeVM_G(4^{++})=3.65(6)(18)GeV, which rules out the 4++4^{++} or mainly 4++4^{++} glueball interpretation for Ο(2230)\xi(2230).Comment: 10 pages and 1 figur

    F_B from moving B mesons

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    We show results for the B meson decay constant calculated both for B mesons at rest and those with non-zero momentum and using both the temporal and spatial components of the axial vector current. It is an important check of lattice systematic errors that all these determinations of f_B should agree. We also describe how well different smearings for the B meson work at non-zero momentum - the optimal smearing has a narrow smearing for the b quark.Comment: Lattice2001(heavyquark

    The QCD String Spectrum and Conformal Field Theory

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    The low energy excitation spectrum of the critical Wilson surface is discussed between the roughening transition and the continuum limit of lattice QCD. The fine structure of the spectrum is interpreted within the framework of two-dimensional conformal field theory.Comment: Lattice2001 (confinement),3 pages,1 figure,uses espcrc2.st

    The glueball spectrum from an anisotropic lattice study

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    The spectrum of glueballs below 4 GeV in the SU(3) pure-gauge theory is investigated using Monte Carlo simulations of gluons on several anisotropic lattices with spatial grid separations ranging from 0.1 to 0.4 fm. Systematic errors from discretization and finite volume are studied, and the continuum spin quantum numbers are identified. Care is taken to distinguish single glueball states from two-glueball and torelon-pair states. Our determination of the spectrum significantly improves upon previous Wilson action calculations.Comment: 14 pages, 8 figures, uses REVTeX and epsf.sty (final version published in Physical Review D
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