We report on a lattice investigation of improved quenched Wilson fermions above and below the confinement-deconfinement phase transition. Results on meson screening masses as well as spatial wave functions are presented. Moreover, the meson dispersion relation is studied. Below the critical temperature we do not observe any significant temperature effect while above T-c the data are consistent with a leading free quark behavior.

We present recent results for meson screening masses with improved quenched Wilson fermions above and below the confinement-deconfinement phase transition including data at finite momentum.

We investigate the limit of vanishing quark mass in quenched lattice QCD with unimproved Wilson fermions at beta = 6.0. Exploiting the correlations of propagators at different time slices we extract pion masses extremely close to the 'chiral limit', despite the presence of 'exceptional configurations'. With this at hand, the existence of quenched chiral logarithms can be demonstrated, provided, finite size effects are small. With reference to the phase diagram proposed by Aoki [1] also the range kappa > kappa(c); is investigated. The width of a potential parity-flavor violating phase can, if at all, hardly be resolved.

In quenched lattice QCD with standard Wilson fermions the quark propagator is computed very close to the chiral limit in the zero-temperature case. Starting from our experience with lattice QED we employ a modified statistical method in order to estimate reliably hadron masses. We discuss the implications for the mechanism of chiral symmetry breaking.

We present first results of a study of two flavour QCD with Wilson fermions at finite temperature. We have used tree level Symanzik improvement in both the gauge and fermion part of the action. In a first step we explore the phase diagramm on an 83 × 4 lattice, with particular emphasis on checking Aoki's conjecture with an improved action.

We present recent results for meson screening masses with quenched Wilson fermions above and below the confinement- deconfinement phase transition. The action used in the simulation is the Sheikholeslami Wohlert action. The quark masses are chosen to be in a range going from light quarks up to the mass of the charm quark. These results are compared with zero temperature Wilson and high temperature staggered data.

We present recent results for meson screening masses with quenched Wilson fermions above and below the confinementdeconfinement phase transition. The action used in the simulation is the Sheikholeslami Wohlert action. The quark masses are chosen to be in a range going from light quarks up to the mass of the charm quark. These results are compared with zero temperature Wilson and high temperature staggered data.