Effects of the quark field on the ghost propagator of lattice Landau gauge QCD

Furui, Sadataka; Nakajima, Hideo

doi:10.1103/physrevd.73.094506

Cited by 55 publications

(102 citation statements)

References 42 publications

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“…As already discussed for other articles from these authors, a massive gluon formula is assumed for the gluon propagator at treelevel, ∆( [259]. In determining this value, the apparent IR-vanishing trend of α gh s was ignored since it was identified to be due to finite size effects [331].…”

Section: Lattice Results For α S In the Irmentioning

confidence: 99%

The QCD running coupling

Deur

Brodsky

Téramond

2016

Progress in Particle and Nuclear Physics

312

236

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We review the present theoretical and empirical knowledge for α s , the fundamental coupling underlying the interactions of quarks and gluons in Quantum Chromodynamics (QCD). The dependence of α s (Q 2 ) on momentum transfer Q encodes the underlying dynamics of hadron physics -from color confinement in the infrared domain to asymptotic freedom at short distances. We review constraints on α s (Q 2 ) at high Q 2 , as predicted by perturbative QCD, and its analytic behavior at small Q 2 , based on models of nonperturbative dynamics. In the introductory part of this review, we explain the phenomenological meaning of the coupling, the reason for its running, and the challenges facing a complete understanding of its analytic behavior in the infrared domain.In the second, more technical, part of the review, we discuss the behavior of α s (Q 2 ) in the high momentum transfer domain of QCD. We review how α s is defined, including its renormalization scheme dependence, the definition of its renormalization scale, the utility of effective charges, as well as "Commensurate Scale Relations" which connect the various definitions of the QCD coupling without renormalization-scale ambiguity. We also report recent significant measurements and advanced theoretical analyses which have led to precise QCD predictions at high energy. As an example of an important optimization procedure, we discuss the "Principle of Maximum Conformality", which enhances QCD's predictive power by removing the dependence of the predictions for physical observables on the choice of theoretical conventions such as the renormalization scheme. In the last part of the review, we discuss the challenge of understanding the analytic behavior α s (Q 2 ) in the low momentum transfer domain. We survey various theoretical models for the nonperturbative strongly coupled regime, such as the light-front holographic approach to QCD. This new framework predicts the form of the quark-confinement potential underlying hadron spectroscopy and dynamics, and it gives a remarkable connection between the perturbative QCD scale Λ and hadron masses. One can also identify a specific scale Q 0 which demarcates the division between perturbative and nonperturbative QCD. We also review other important methods for computing the QCD coupling, including lattice QCD, the Schwinger-Dyson equations and the GribovZwanziger analysis. After describing these approaches and enumerating their conflicting predictions, we discuss the origin of these discrepancies and how to remedy them. Our aim is not only to review the advances in this difficult area, but also to suggest what could be an optimal definition of α s (Q 2 ) in order to bring better unity to the subject.2

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Section: Lattice Results For α S In the Irmentioning

confidence: 99%

The QCD running coupling

Deur

Brodsky

Téramond

2016

Progress in Particle and Nuclear Physics

312

236

View full text Add to dashboard Cite

show abstract

“…[16][17][18][19][20]). Recent lattice QCD calculations suggest, however, that such renomalization can be of the order of 30% (or even more) at zero momentum [8][9][10]. Moreover, these calculations also show that the quark masses tend to their asymptotic values in a rather soft way.…”

Section: Introductionmentioning

confidence: 87%

“…We fix the values of m c and hq " qi 1=3 to reasonable values m c ¼ 5:7 MeV and hq " qi 1=3 ¼ À240 MeV determining the rest of the parameters so as to reproduce the empirical values f ¼ 92:4 MeV and m ¼ 139 MeV, and Zð0Þ ¼ 0:7 which is within the range of values suggested by recent lattice calculations [8,10].…”

Section: Determination Of the Model Parametersmentioning

confidence: 94%

“…In fact, nonlocality arises naturally in quantum field theory and, particularly, in several well-established approaches to low-energy quark dynamics, as, e.g., the instanton liquid model [6] and the Schwinger-Dyson resummation techniques [7]. Lattice QCD calculations [8][9][10] also indicate that quark interactions should act over a certain range in the momentum space. Moreover, it has been argued that nonlocal extensions of the NJL model do not show some of the above mentioned inconveniences of the local theory.…”

Section: Introductionmentioning

confidence: 98%

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Nonlocal chiral quark models with wavefunction renormalization: Sigma properties andπ−πscattering parameters

2008

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We analyze the sigma meson mass and width together with the pion-pion scattering parameters in the context of nonlocal chiral quark models with wave function renormalization (WFR). We consider both nonlocal interactions based on the frequently used exponential form factor, and on fits to the quark mass and renormalization functions obtained in lattice calculations. In the case of the sigma properties, we obtain results which are less dependent on the parametrization than in the standard local Nambu-JonaLasinio model, and which are in reasonable agreement with the recently reported empirical values. We also show that the inclusion of the WFR tend to improve the description of the -scattering parameters, with the lattice inspired parametrization providing the best overall results. Finally, we analyze the connection of the nonlocal quark models discussed here with chiral perturbation theory, and present the model predictions for the low-energy constants relevant for -scattering to Oð4Þ in the chiral expansion.

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“…Using the gap equation arising from the horizon condition, one finds that [3,22,23,25,26,27] This enhancement remains valid in the presence of A 2 [25,26]. The infrared enhancement of the ghost propagator in the Landau gauge has also been observed from lattice simulations [29,28] or solutions of the Schwinger-Dyson equations [30,31,32]. The Gribov restriction and A 2 also affect the gluon propagator in a nontrivial fashion, more precisely one finds [25,26] …”

Section: Restriction To the Gribov Horizonmentioning

confidence: 75%