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 theoretical issues in connection with t...

We compute the b quark mass from dynamical lattice QCD with clover quarks. The calculation is done at a fixed lattice spacing with sea quark masses as low as half the strange quark mass. Our final result is m b (m b) = 4.25(2)(11) GeV, where the first error is statistical and the last error is the systematic uncertainty.

We review some decays that require knowledge of the decay constants of 0 + heavy-light mesons. We compute the decay constants of P-wave heavy-light mesons from unquenched lattice QCD at a single lattice spacing. For the charm-strange meson we obtain the decay constant: fD s 0 + = 340(110) MeV using our normalisation conventions. We obtain the f static Ps (static-strange P-wave) decay constant a...

We review the theory that predicts that the decay constant of the excited light pseudo-scalar mesons are suppressed in the chiral limit relative to the pion decay constant. We compute the decay constant of the first excited pion (π′) using unquenched QCD at a fixed lattice spacing with sea quarks of mass as low as a third the mass of the strange quark. The final result is very sensitive to the ...

We study gluon propagator in Landau gauge with lattice QCD, where we use an improved lattice action. The calculation of gluon propagator is performed on lattices with the lattice spacing from 0.40fm to 0.24fm and with the lattice volume from (2.40fm) 4 to (4.0fm) 4. We try to fit our results by two different ways, in the first one we interpret the calculated gluon propagators as a function of t...

By (a) using an expression for the lattice potential of QCD in terms of a continuum running coupling and (b) globally parameterizing this coupling to interpolate between 2(or higher-) loop QCD in the UV and the flux tube prediction in the IR, we can perfectly fit lattice data for the potential down to one lattice spacing and at the same time extract the running coupling to high precision. This ...

I have performed scaling tests using quenched spectroscopy of a family of fermion actions which have a hypercubic kinetic term, gauge connections built of smeared links, and an anomalous magnetic moment term. These actions show improved rotational invariance compared to the standard Wilson action and to the tadpole-improved clover action. Hyperfine splittings are improved compared to the standa...

We present a p-adic and non-archimedean version of Ahlfors’ Five Islands Theorem for meromorphic functions, extending an earlier theorem of the author for holomorphic functions. In the non-archimedean setting, the theorem requires only four islands, with explicit constants. We present examples to show that the constants are sharp and that other hypotheses of the theorem cannot be removed.

Model for studying coupling dependence on lattice spacing a in gluodynamics is suggested. The model predicts g → g0 > 0 with a→ 0. Free energy density in the model does not depend on temperature.