Related papers: Perturbative QCD Potential and String Tension
We show that the perturbatively-improved gluon action for QCD, once it is tadpole-improved, gives accurate results even with lattice spacings as large as 0.4~fm. {\em No\/} tuning of the couplings is required. Using this action and lattice…
The analytization procedure which allows one to remove nonphysical singularities of the QCD running coupling constant $\bar\alpha_s(q^2)$ in the infrared region is applied to standard as well as to iterative solutions of the two-loop…
The improved light-cone distribution amplitudes (LCDAs) of the $\Lambda$ baryon are examined on the basis of the QCD conformal partial wave expansion approach. The calculations are carried out to the next-to-leading order of conformal spin…
We analyze the divergent behaviour of the perturbative expansion in QCD, focusing on some well-known sources of divergence such as renormalons, instantons and the Landau pole divergence. We determine at which perturbative order each of…
We investigate the Taylor expansion of the baryon number susceptibility, and hence, pressure, in a series in the baryon chemical potential (mu_B) through a lattice simulation with light dynamical staggered quarks at a finer lattice cutoff…
QCD perturbation theory using quark and gluon propagators that have an extra term at zero four-momentum is equivalent to standard PQCD in the presence of massless quark and gluon pairs in the perturbative vacuum. We verify at low orders in…
Using the general argument in Borel resummation of perturbation theory that links the divergent perturbation theory to the nonperturbative effect we argue that the nonperturbative effect associated with the perturbation theory should have a…
The equation of state of Quantum Chromodynamics (QCD) at finite density is currently known only in a limited range in the baryon chemical potential $\mu_B$. This is due to fundamental shortcomings of traditional methods such as Taylor…
Estimates of higher-order contributions for perturbative series in QCD, in view of their asymptotic nature, are delicate, though indispensable for a reliable error assessment in phenomenological applications. In this work, the Adler…
We discuss our present knowledge of $\alpha_s$, the fundamental running coupling or effective charge of Quantum Chromodynamics (QCD). A precise understanding of the running of $\alpha_s(Q^2) $ at high momentum transfer, $Q$, is necessary…
The two-loop invariant (running) coupling of QCD is written in terms of the Lambert W function. The analyticity structure of the coupling in the complex Q^2-plane is established. The corresponding analytic coupling is reconstructed via a…
The asymptotical behaviour of the QCD coupling strength is considered. Its upper bound is found from the present experimental data. The assumption about the finite asymptotical value of the coupling strength leads to the energy scale where…
We construct a non-perturbative method to investigate the phase structure of the scalar theory at finite temperature. The derivative of the effective potential with respect to the mass square is expressed in terms of the full propagator.…
We discuss a simple method to evaluate the QCD corrections to $\Delta\rho$. It assumes that the perturbative expansion in terms of $\ms$ parameters is meaningful and, unlike other studies, exploits significant available information…
We evaluate the static QCD potential to two--loop order. Compared to a previous calculation a sizable reduction of the two--loop coefficient $a_2$ is found.
We non-perturbatively calculate the scale dependence of the static axial current in the Schroedinger functional scheme by means of a recursive finite-size scaling technique, taking the continuum limit in each step. The bare current in the…
A summary of the current understanding of methods of analytical higher order perturbative computations of total cross sections and decay widths in Quantum Chromodynamics is presented. As examples, the total cross section in electron…
The leading-order perturbative QCD (pQCD) predictions to nucleon electromagnetic form factors were first made in late 70s. In this Letter for the first time we accomplish the calculation of the next-to-leading-order (NLO) QCD corrections to…
The non-perturbative domain of QCD contains confinement, chiral symmetry breaking, and the bound state spectrum. For the calculation of the latter, the Coulomb gauge is particularly well-suited. Access to these non-perturbative properties…
Taylor expansion of the equation of state of QCD suffers from shortcomings at chemical potentials $\mu_B \geq (2-2.5)T$. First, one faces difficulties inherent in performing such an expansion with a limited number of coefficients; second,…