PaperPanorama

HEP Lattice·hep-lat

Mon·Oct 10, 2005

11 papers—9 primary·2 cross-listed·reconstructed*

All11Primary9Cross-lists2
  1. 01*

    Study of 1/m corrections in HQET

    Shunsuke Negishi🇯🇵 · Hideo Matsufuru🇯🇵 · Tetsuya Onogi🇯🇵 · Takashi Umeda🇺🇸

    We report our exploratory study on the matching condition of HQET with QCD including 1/m corrections. We introduce a new observable from the dependence of the heavy-light effective energy on the twisted boundary condition parameter , which could be used to match the kinetic term . Carrying out quenched QCD simulations for fixed lattice spacing in small volumes with O(a)-improved Wilson fermions, we study the 1/m dependence of this observable, from which the static limit and 1/m coefficient can be extracted. We also compare our preliminary result with HQET.

    hep-latPoS(2006)·0 citations
  2. 02*

    Meson correlators in a finite volume near the chiral limit

    Hidenori Fukaya (1)🇯🇵 · Shoji Hashimoto (2 and 3)🇯🇵 · Kenji Ogawa (3) ((1) Yukawa Institute for Theoretical Physics, (2) High Energy Accelerator Research Organization, (3) The Graduate University for Advanced Studies)🇯🇵

    We report on the results of our calculation of meson correlators in a finite volume. The calculation is carried out in the quenched approximation near the chiral limit (down to Mq = 2.6 MeV) using the overlap fermion. For these small quark masses, the scalar and pseudo-scalar correlators are well approximated with a few hundred eigenmodes. The results for both connected and disconnected correlators are compared with the theoretical predictions of quenched chiral perturbation theory.

    hep-latPoS(2006)·1 citation
  4. 04*

    Anatomy of String Breaking in QCD

    Zdravko Prkacin (1)🇩🇪 · Gunnar S Bali (2)🇬🇧 · Thomas Dussel (3)🇩🇪 · Thomas Lippert (1 and 3)🇩🇪 · Hartmut Neff (4)🇬🇧 · Klaus Schilling (1) ((1) Uni Wuppertal, (2) Uni Glasgow, (3) ZAM, FZ Juelich, (4) CCS, UC London)🇩🇪

    We investigate the string breaking mechanism in n_f=2 QCD. We discuss the lattice techniques used and present results on energy levels and mixing angle of the static BBbar|QbarQ two-state system. The string breaking is visualized, by means of an animation of the action density distribution as a function of the static colour source-antisource separation.

    hep-latPoS(2006)·13 citations
  5. 05*

    Distributing the chiral and flavour components of Dirac-Kahler fermions across multiple lattices

    Steven Watterson🇮🇪 · J. Sexton🇮🇪

    We use a specific implementation of discrete differential geometry to describe Dirac-Kahler fermions in such a way that we can separate their chiral and flavour components. The formulation introduces additional lattices so that on each lattice there is a single field of definate chirality. Within this framework, we define an non-compact Abelian gauge theory.

    hep-latPoS(2006)·1 citation
  6. 06*

    High Precision Fundamental Constants using Lattice Perturbation Theory

    Quentin Mason🇬🇧 · Howard Trottier🇨🇦 · Ron Horgan🇬🇧

    The HPQCD collaboration has a program for determining the fundamental constants of the Standard Model Lagrangian from lattice QCD. The most accurate method of doing this uses the n_f=2+1 improved staggered MILC ensembles with chiral fitting and multi-loop perturbative renormalisation to connect to the continuum \msbar scheme. This program has already been very successful with the recent strong coupling constant determination at three-loops from 28 observables at three lattice spacings, and the one-loop light quark mass calculation last year. Here a preliminary result is presented for the first-ever lattice determination of the two-loop multiplicative quark mass renormalisation. The perturbative calculation involved was automated in the generation of the Feynman rules, and the generation and coding of all of the roughly 30 Feynman diagrams. The full formal framework for lattice quark mass renormalisation is given, including the cancellation of infrared divergences in intermediate diagrams. The result was checked by evaluation in three separate gauges and by two authors independently, showing the incredible flexibility and power of this perturbative methodology. Our preliminary result for the two-loop perturbative matching factor, and of systematic errors associated with higher-orders, gives \msbar masses at a 2 GeV scale of MeV, and MeV, where the respective uncertainties are from lattice statistical, lattice systematic, perturbative, and electromagnetic and isospin effects. The perturbative errors are a factor of two smaller than in our previous study, and we anticipate reducing this somewhat further from additional analysis of the systematics.

    hep-latPoS(2006)·10 citations
  7. 07*

    Notes on (twisted) lattice supersymmetry

    Simon Catterall🇺🇸

    We describe a new approach to the problem of putting supersymmetric theories on the lattice. The basic idea is to discretize a {\it twisted} formulation of the supersymmetric theory. For certain theories with extended supersymmetry these twisted formulations contain only integer spin fields. The twisting exposes a scalar nilpotent supercharge which generates an exact lattice symmetry. We gives examples from quantum mechanics, sigma models and Yang-Mills theories.

    hep-lat7 citations
  8. 08*

    Deconfinement phase transitions in external fields

    Paolo Cea🇮🇹 · Leonardo Cosmai🇮🇹

    We compare vacuum dynamics of abelian versus non abelian lattice gauge theories in presence of external fields. We find that the deconfinement temperature of non abelian theories depends on the strength of a constant abelian chromomagnetic field end eventually goes to zero. On the contrary such an effect is not shared by abelian theories. We argue on the relevance of this result to understand the QCD vacuum.

    hep-latPoS(2006)·4 citations
  9. 09*

    Probing the chiral phase transition of N_f=2 clover fermions with valence overlap fermions

    V. Weinberg🇩🇪 · E.-M. Ilgenfritz🇩🇪 · K. Koller🇩🇪 · Y. Koma🇩🇪 · G. Schierholz🇩🇪 · T. Streuer🇩🇪

    Overlap fermions are a powerful tool for investigating the chiral and topological structure of the vacuum and the thermal states of QCD. We study various chiral and topological aspects of the finite temperature phase transition of N_f=2 flavours of O(a) improved Wilson fermions, using valence overlap fermions as a probe. Particular emphasis is placed upon the analysis of the spectral density and the localisation properties of the eigenmodes as well as on the local structure of topological charge fluctuations in the vicinity of the chiral phase transition. The calculations are done on 16^3x8 lattices generated by the DIK collaboration.

    hep-latPoS(2006)·6 citations
  10. 10*

    Strings from Various Perspectives: QCD, Lattices, String Theory and Toy Models

    M. Shifman🇺🇸

    I review the status of the issue of the k-string tension in Yang-Mills theory. After a summary of known facts I discuss a weakly coupled four-dimensional Yang-Mills theory that supports non-Abelian strings and can, in certain aspects, serve as a toy model for QCD strings. In the second part of the talk I present original results obtained in a two-dimensional toy model which provides some evidence for the sine formula.

    ↳ hep-phhep-lathep-thActa Phys.Polon.B(2005)·18 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.