2,809 research outputs found

    Monopole Condensation and Polyakov Loop in Finite-Temperature Pure QCD

    Get PDF
    We study the relation between the abelian monopole condensation and the deconfinement phase transition of the finite-temperature pure QCD. The expectation value of the monopole contribution to the Polyakov loop becomes zero when a long monopole loop is distributed uniformly in the configuration of the confinement phase. On the other hand, it becomes non-zero when the long monopole loop disappears in the deconfinement phase. We also discuss the relation between the monopole behaviors and the usual interpretation of the spontaneous breaking of Z(N) symmetry in finite-temperature SU(N) QCD. It is found that the boundary condition of the space direction is important to understand the Z(N) symmetry in terms of the monopoles.Comment: 3 pages, latex, 8 figures, Talk presented at LATTICE96(topology

    Improved Currents for Heavy Quarks

    Full text link
    We discuss lattice artifacts for matrix elements of hadrons containing one or more heavy quark. In particular, we analyze interrelations between lattice artifacts and the 1/mQ1/m_Q expansion. The implications for calculations of heavy-light decay constants and of semi-leptonic form factors are discussed.Comment: 3 pages, no figures, uuencoded PostScript, proceedings of Lattice '94. LaTeX at ftp://fnth06.fnal.gov/pub/Fermilab-Pub/95.00

    Binding Energies in Nonrelativistic Field Theories

    Get PDF
    Relativistic corrections communicate the binding energy of a bound state to its kinetic mass. This mechanism is reviewed and used to explain anomalous results of Collins, Edwards, Heller, and Sloan (hep-lat/9512026), which compared rest and kinetic masses of heavy-light mesons and quarkonia.Comment: 4 pages, 1 figure, poster presented at LATTICE96(heavy quarks

    Perturbative and Non-perturbative Corrections to BD()lνB\to D^{(*)}l\nu

    Full text link
    It is shown that certain double ratios introduced for computing semileptonic form factors are accurate to order 1/mQ21/m_Q^2, even when the action and current are accurate to order 1/mQ1/m_Q.Comment: Lattice99(heavyquarks); 3 + epsilon pp. LaTe

    B and D Mesons in Lattice QCD

    Get PDF
    Computational and theoretical developments in lattice QCD calculations of B and D mesons are surveyed. Several topical examples are given: new ideas for calculating the HQET parameters \bar{\Lambda} and \lambda_1; form factors needed to determine |V_{cb}| and |V_{ub}|; bag parameters for the mass differences of the B mesons; and decay constants. Prospects for removing the quenched approximation are discussed.Comment: Mini-review from the XXXth International Conference on High Energy Physics, Osaka, Japa

    Twenty-first Century Lattice Gauge Theory: Results from the QCD Lagrangian

    Full text link
    Quantum chromodynamics (QCD) reduces the strong interactions, in all their variety, to a simple nonabelian gauge theory. It clearly and elegantly explains hadrons at short distances, which has led to its universal acceptance. Since its advent, however, many of its long-distance, emergent properties have been believed to be true, without having been demonstrated to be true. This paper reviews a variety of results in this regime that have been established with lattice gauge theory, directly from the QCD Lagrangian. This body of work sheds light on the origin of hadron masses, its interplay with dynamical symmetry breaking, as well as on other intriguing features such as the phase structure of QCD. In addition, nonperturbative QCD is quantitatively important to many aspects of particle physics (especially the quark flavor sector), nuclear physics, and astrophysics. This review also surveys some of the most interesting connections to those subjects.Comment: invited review for Annual Reviews of Nuclear and Particle Science (2012); 21 pp., 4 tables, 6 figures. v2: Figures 2 and 5 updated; references added; many minor wording changes and clarifications; conforms closely to accepted versio

    Lattice QCD Calculations of Leptonic and Semileptonic Decays

    Get PDF
    In lattice QCD, obtaining properties of heavy-light mesons has been easier said than done. Focusing on the BB meson's decay constant, it is argued that towards the end of 1997 the last obstacles were removed, at least in the quenched approximation. These developments, which resulted from a fuller understanding and implementation of ideas in effective field theory, bode well for current studies of neutral meson mixing and of semileptonic decays.Comment: Invited talk at the Workshop on Heavy Quarks at Fixed Target, October 10-12, 1998, Fermi National Accelerator Laborator

    Dynamics of Langevin Simulation

    Get PDF
    This chapter [of a supplement to Prog. Theo. Phys.] reviews numerical simulations of quantum field theories based on stochastic quantization and the Langevin equation. The topics discussed include renormalization of finite step-size algorithms, Fourier acceleration, and the relation of the Langevin equation to hybrid stochastic algorithms and hybrid Monte Carlo.Comment: 20 p

    Lattice QCD and the Unitarity Triangle

    Get PDF
    Theoretical and computational advances in lattice calculations are reviewed, with focus on examples relevant to the unitarity triangle of the CKM matrix. Recent progress in semi-leptonic form factors for B -> pi l nu and B -> D* l nu, as well as the parameter \xi in B-Bbar mixing, are highlighted.Comment: Invited talk at the 9th International Symposium on Heavy Flavor Physics, September 10-13, 2001, Caltech, Pasadena. 11 pages, 5 figure
    corecore