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Using a new type of simulation algorithm for the standard SU(3) lattice gauge theory that yields results with unprecedented precision, we confirm the presence of a γ/r correction to the static quark potential at large distances r, with a coefficient γ as predicted by the bosonic string theory. In both three and four dimensions, the transition from(More)
Lattice QCD with Wilson quarks and a chirally twisted mass term represents a promising alternative regularization of QCD, which does not suffer from unphysical fermion zero modes. We show how the correlation functions of the renormalized theory are related to the theory with a standard parameterization of the mass term. In particular we discuss the(More)
A non-perturbative nite-size scaling technique is used to study the evolution of the running coupling (in a certain adapted scheme) in the SU(3) Yang-Mills theory. At low energies contact is made with the fundamental dynamical scales, such as the string tension K, while at larger energies the coupling is shown to evolve according to perturbation theory. In(More)
The conservation of the isovector axial current in lattice QCD with mass-less Wilson quarks is studied to one-loop order of perturbation theory. Following a strategy described in a previous publication, the O(a) counterterm required for on-shell improvement of the current is computed. We also connrm an earlier result of Wohlert for the coeecient in front of(More)
The dominant cutoo eeects in lattice QCD with Wilson quarks are proportional to the lattice spacing a. In particular, the isovector axial current satisses the PCAC relation only up to such eeects. Following a suggestion of Symanzik, they can be cancelled by adding local O(a) correction terms to the action and the axial current. We here address a number of(More)
In the presence of a static quark-antiquark pair, the spectrum of the lowlying states in SU(N) gauge theories is discrete and likely to be described, at large quark separations r, by an effective string theory. The expansion of the excitation energies in powers of 1/r, which derives from the latter, involves an increasing number of unknown couplings that(More)
We present results at one-loop order of perturbation theory for various improvement coefficients in on-shell O(a) improved lattice QCD. In particular we determine the additive counterterm required for on-shell improvement of the isovector vector current. Employing a general mass-independent renormalization scheme we also obtain the coefficients of the O(a)(More)
By matching 1/m2 divergences in finite-volume two-point correlation functions of the scalar or pseudoscalar densities with those obtained in chiral perturbation theory, we derive a relation between the Dirac operator zero-mode eigenfunctions at fixed non-trivial topology and the low-energy constants of QCD. We investigate the feasibility of using this(More)