3,561 research outputs found

    Four-momentum boosted Fermion fields

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    A formulation of the fermion action is discussed which includes an explicit four momentum boost on the field prior to discretisation. This is used to shift the zero of lattice momentum to lie near one of the on-shell quark poles. The positive pole is selected if we wish to describe a valence quark, and negative pole for a valence anti-quark. Like NRQCD, the typical lattice momenta involved in hadronic correlation functions can be kept small: of order O(aΛQCD)O(a \Lambda_{\rm QCD}), rather than O(amQ)O(a m_Q) even when describing heavy quarks. If we expand around the particle pole, the anti-particle correlator will be poorly described for large amQa m_Q. However, in that case the anti-particle will be far off shell and will only affect unphysical, renormalization factors. The formulation produces the correct continuum limit, and preliminary results have been obtained (for an unimproved action) of both the one-loop self energy and a non-perturbative correlation function.Comment: Talk presented at Lattice2003(heavy). 3 pages, 1 figur

    Charmed hadron physics in quenched anisotropic lattice QCD

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    We investigate the anisotropic lattice with O(a)O(a) improved quark action as a candidate of framework in which we can treat both the heavy and light quark region in the same manner and systematically reduce the systematic uncertainties. To examine applicability of anisotropic lattice, we calculate the charmed meson spectrum and decay constants in quenched approximation. We find consistent result with most advanced results on isotropic lattices.Comment: 3 pages, 1 figure, contribution to Fifth KEK Topical Conference - Frontiers in Flavor Physics -, Tsukuba, Japan, November 20-22, 200

    Wave functions and their use in spectroscopy and phenomenology

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    We describe the calculation of Coulomb gauge wave functions for light quark systems, and their use as interpolating fields for excited state spectroscopy.Comment: 4 pages latex with lat92 macro plus 4 postscript figs, COLO-HEP-29

    Relativistic Quarkonia from Anisotropic Lattices

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    We report on new results for the spectrum of quarkonia using a fully relativistic approach on anisotropic lattices with quark masses in the range from strange to bottom. A fine temporal discretisation also enables us to resolve excitations high above the ground state. In particular we studied the mass dependence and scaling of hybrid states.Comment: 4 pages, 5 figures. Lattice 2000 (Heavy Quark Physics

    Properties of Low-Lying Heavy-Light Mesons

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    We present preliminary results for the B meson decay constant and masses of low-lying heavy-light mesons in the static limit. Calculations were performed on the lattice in the quenched approximation using multistate smearing functions generated from a Hamiltonian for a spinless relativistic quark. The 2S--1S and 1P--1S mass splittings are measured. Using the 1P--1S charmonium splitting to set the overall scale, the ground state decay constant, f_B, is 319 +- 11 (stat) MeV.Comment: 8 pages, 9 figures, UCLA/92/TEP/4

    The Spectrum from Lattice NRQCD

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    I review recent results for heavy-heavy spectroscopy using Lattice NRQCD. The NRQCD collaboration reports that spin-independent splittings for the Υ\Upsilon are scaling for a sensible range of β\beta values in the quenched approximation. Spin-dependent splittings are not, if the scale is set by spin-independent splittings. Results which include higher order spin-dependent relativistic and discretisation corrections show differences from previous (NRQCD collaboration) results without these. As expected, the differences are small for Υ\Upsilon but rather large for charmonium. New results from the SESAM collaboration for Υ\Upsilon spectroscopy on configurations with Wilson dynamical fermions show good agreement with previous results on HEMCGC configurations with staggered dynamical fermions.Comment: 10 pages, Latex. 10 figures, 7 in postscript. Review for Tsukuba worksho

    Non-Relativistic QCD for Heavy Quark Systems

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    We employ a nonrelativistic version of QCD (NRQCD) to study heavy quark-antiquark bound states in the lowest approximation without fine structure. We use gluon configurations on a 16^3 by 48 lattice at beta=6.2 from the UKQCD collaboration. For quark masses in the vicinity of the b we obtain bound state masses for S, P and both types of D wave. We also detect signals for two types of hybrids (quark,antiquark,gluon states). The results are sufficiently accurate to confirm that the values of the D wave mass from both lattice D waves coincide indicating that the cubical invariance of the lattice is restored to full rotational invariance at large distance. Our results also show that the S-P splitting is indeed insensitive to variations in the bare quark mass from Ma=1.0 to Ma=1.9.Comment: 13 pages, DAMTP-92-7

    Exotic meson spectroscopy from the clover action at beta = 5.85 and 6.15

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    We repeat our original simulations of the hybrid meson spectrum using the clover action, as a check on lattice artifacts. Our results for the 1-+ masses do not substantially change. We present preliminary results for the wave function of the 1-+ state in Coulomb gauge.Comment: LATTICE98(spectrum) 3 latex pages and two postscript figures. Contribution to lattice 9

    Heavy quark physics from lattice QCD

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    I review the current status of lattice calculations of heavy quark quantities. Particular emphasis is placed on leptonic and semileptonic decay matrix elements.Comment: Lattice2001(plenary), 12 pages, 6 figures. Table 1 updated and typos in Figure 6 correcte

    Masses and Decay Constants of Heavy-Light Mesons Using the Multistate Smearing Technique

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    We present results for f_B and masses of low-lying heavy-light mesons. Calculations were performed in the quenched approximation using multistate smearing functions generated from a spinless relativistic quark model Hamiltonian. Beta values range from 5.7 to 6.3, and light quark masses corresponding to pion masses as low as 300 MeV are computed at each value. We use the 1P--1S charmonium splitting to set the overall scale.Comment: 9 pages, 13 figures, and 5 tables as a single 193K compressed and uuencoded Postscript file, FERMILAB--CONF--93/376-
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