scholarly journals Gauge-fixed Lattice QCD and the dispersion relation of Wilson fermions

2022 ◽  
Vol 258 ◽  
pp. 02003
Author(s):  
Giuseppe Burgio ◽  
Hannes Vogt
Keyword(s):  
Dispersion Relation ◽  
Lattice Qcd ◽  
Correlation Functions ◽  
Landau Gauge ◽  
Coulomb Gauge ◽  
Tree Level ◽  
Wilson Fermions

We show that, when investigating Wilson-fermions correlation functions on the lattice, one is bound to encounter major difficulties in defining their dispersion relation, even at tree level. The problem is indeed quite general and, although we stumbled upon it while studying Coulomb-gauge applications, it also affects gauge fixed studies in covariant gauges, including their most popular version, Landau gauge. In this paper we will discuss a solution to this problems based on a redefinition of the kinematic momentum of the fermion.

scholarly journals Non-perturbative improvement of the axial current in Nf=3 lattice QCD with Wilson fermions and tree-level improved gauge action

2015 ◽  
Vol 896 ◽  
pp. 555-568 ◽  
Author(s):  
John Bulava ◽  
Michele Della Morte ◽  
Jochen Heitger ◽  
Christian Wittemeier
Keyword(s):  
Lattice Qcd ◽  
Axial Current ◽  
Tree Level ◽  
Gauge Action ◽  
Wilson Fermions

scholarly journals Determination of $c_A$ in three-flavour lattice QCD with Wilson fermions and tree-level improved gauge action

2014 ◽  
Author(s):  
Christian Wittemeier ◽  
Michele Della Morte ◽  
John Bulava ◽  
Jochen Heitger
Keyword(s):  
Lattice Qcd ◽  
Tree Level ◽  
Gauge Action ◽  
Wilson Fermions

scholarly journals A window on infrared QCD with small expansion parameters

2021 ◽  
Author(s):  
Marcela Peláez ◽  
Urko Reinosa ◽  
Julien Serreau ◽  
Matthieu Tissier ◽  
Nicolas Wschebor
Keyword(s):  
Correlation Functions ◽  
Chemical Potential ◽  
Landau Gauge ◽  
Spontaneous Breaking ◽  
Tree Level ◽  
Coupling Constant ◽  
Long Distance ◽  
Gauge Sector ◽  
Small Parameters ◽  
Distance Properties

Abstract Lattice simulations of the QCD correlation functions in the Landau gauge have established two remarkable facts. First, the coupling constant in the gauge sector — defined, e.g., in the Taylor scheme— remains finite and moderate at all scales, suggesting that some kind of perturbative description should be valid down to infrared momenta. Second, the gluon propagator reaches a finite nonzero value at vanishing momentum, corresponding to a gluon screening mass. We review recent studies which aim at describing the long-distance properties of Landau gauge QCD by means of the perturbative Curci-Ferrari model. The latter is the simplest deformation of the Faddeev-Popov Lagrangian in the Landau gauge that includes a gluon screening mass at tree-level. There are, by now, strong evidences that this approach successfully describes many aspects of the infrared QCD dynamics. In particular, several correlation functions were computed at one- and two-loop orders and compared with ab-initio lattice simulations. The typical error is of the order of ten percent for a one-loop calculation and drops to few percents at two loops. We review such calculations in the quenched approximation as well as in the presence of dynamical quarks. In the latter case, the spontaneous breaking of the chiral symmetry requires to go beyond a coupling expansion but can still be described in a controlled approximation scheme in terms of small parameters. We also review applications of the approach to nonzero temperature and chemical potential.

scholarly journals LATTICE QCD GLUON PROPAGATORS NEAR TRANSITION TEMPERATURE

2012 ◽  
Vol 27 (09) ◽  
pp. 1250050 ◽  
Author(s):  
V. G. BORNYAKOV ◽  
V. K. MITRJUSHKIN
Keyword(s):  
Transition Temperature ◽  
Lattice Qcd ◽  
Finite Volume ◽  
Momentum Space ◽  
Transition Point ◽  
Gluon Propagator ◽  
Landau Gauge ◽  
Volume Dependence ◽  
Gauge Fixing ◽  
Two Phases

Landau gauge gluon propagators are studied numerically in the SU (3) gluodynamics as well as in the full QCD with the number of flavors nF = 2 using efficient gauge fixing technique. We compare these propagators at temperatures very close to the transition point in two phases: confinement and deconfinement. The electric mass mE has been determined from the momentum space longitudinal gluon propagator. Gribov copy effects are found to be rather strong in the gluodynamics, while in the full QCD case they are weak ("Gribov noise"). Also we analyze finite volume dependence of the transverse and longitudinal propagators.

GAUGE INDEPENDENCE OF THE FERMION DAMPING RATE IN A HOT PLASMA - LANDAU GAUGE VS COULOMB GAUGE

1993 ◽  
Vol 08 (08) ◽  
pp. 739-748
Author(s):  
H. NAKKAGAWA ◽  
A. NIÉGAWA ◽  
B. PIRE
Keyword(s):  
Perturbation Theory ◽  
Gluon Propagator ◽  
Landau Gauge ◽  
Coulomb Gauge ◽  
Leading Order ◽  
Loop Order ◽  
Hard Thermal Loop ◽  
Hot Plasma ◽  
Damping Rate

The damping rate of a heavy muon/quark in a hot QED/QCD plasma is calculated in the Landau gauge to the effective one-loop order in the resummed perturbation theory of Braaten and Pisarski. For both a muon/quark at rest and in an energetic case we obtain to leading order the same result as in the Coulomb gauge. Resummation of hard-thermal loop corrections to the photon/gluon propagator is of key importance for this gauge independence.

scholarly journals Mass spectra of heavy pseudoscalars using instantaneous Bethe–Salpeter equation with different kernels

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
Wei Li ◽  
Ying-Long Wang ◽  
Tai-Fu Feng ◽  
Guo-Li Wang
Keyword(s):  
Mass Spectra ◽  
Scalar Potential ◽  
Landau Gauge ◽  
Mass Splitting ◽  
Coulomb Gauge ◽  
Exchange Vector ◽  
Feynman Gauge ◽  
Vector Potentials ◽  
Time Component ◽  
Linear Scalar

Abstract We solved the instantaneous Bethe–Salpeter equation for heavy pseudoscalars in different kernels, where the kernels are obtained using linear scalar potential plus one gluon exchange vector potentials in Feynman gauge, Landau gauge, Coulomb gauge and time-component Coulomb gauge. Since we cannot give a complete QCD-based calculation, the results are gauge dependent. We compared the obtained mass spectra of heavy pseudoscalars between different kernels, found that using the same parameters we obtain the smallest mass splitting in time-component Coulomb gauge, the similar largest mass splitting in Feynman and Coulomb gauges, middle size splitting in Landau gauge.

scholarly journals QCD Factorization and PDFs from Lattice QCD Calculation

2015 ◽  
Vol 37 ◽  
pp. 1560041 ◽  
Author(s):  
Yan-Qing Ma ◽  
Jian-Wei Qiu
Keyword(s):  
Euclidean Space ◽  
Minkowski Space ◽  
Lattice Qcd ◽  
Correlation Functions ◽  
Parton Distribution ◽  
Distribution Functions ◽  
Matrix Elements ◽  
Parton Distribution Functions ◽  
Qcd Factorization ◽  
The Matrix

In this talk, we review a QCD factorization based approach to extract parton distribution and correlation functions from lattice QCD calculation of single hadron matrix elements of quark-gluon operators. We argue that although the lattice QCD calculations are done in the Euclidean space, the nonperturbative collinear behavior of the matrix elements are the same as that in the Minkowski space, and could be systematically factorized into parton distribution functions with infrared safe matching coefficients. The matching coefficients can be calculated perturbatively by applying the factorization formalism on to asymptotic partonic states.

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