ar X iv : h ep - l at / 0 11 00 15 v 1 5 O ct 2 00 1 1 Chirally improved Dirac operators : Studying the sensitivity to topological excitations for zero and finite temperature ∗

ar X iv : h ep - l at / 0 11 00 12 v 1 5 O ct 2 00 1 1 Center vortex model for the infrared sector of Yang - Mills theory ∗

A model for the infrared sector of SU(2) Yang-Mills theory, based on magnetic vortices represented by (closed) random surfaces, is presented. The model quantitatively describes both confinement (including the finite-temperature transition to a deconfined phase) and the topological susceptibility of the Yang-Mills ensemble. A first (quenched) study of the spectrum of the Dirac operator furthermo...

ar X iv : h ep - l at / 0 11 00 06 v 1 2 O ct 2 00 1 1 Matrix elements of ∆ S = 2 operators with Wilson fermions

ar X iv : h ep - l at / 0 11 00 06 v 2 3 O ct 2 00 1 1 Matrix elements of ∆ S = 2 operators with Wilson fermions

ar X iv : h ep - l at / 0 41 00 06 v 1 5 O ct 2 00 4 The pion form factor on the lattice at zero and finite temperature

We calculate the electromagnetic form factor of the pion in quenched lattice QCD. The non-perturbatively improved Sheikoleslami-Wohlert lattice action is used together with the consistently O(a) improved current. We calculate the pion form factor for masses down to mπ = 360 M eV , extract the charge radius, and extrapolate toward the physical pion mass. In the second part, we discuss results fo...

ar X iv : h ep - l at / 0 11 01 63 v 2 2 2 O ct 2 00 1 1 Spectral density calculations in a heavy - light meson - meson system ∗

A system of two static quarks, at fixed distances r, and two light quarks is studied on an anisotropic lattice. Excitations by operators emphasizing quark or gluon degrees of freedom are examined. The maximum entropy method is applied in the spectral analysis. These simulations ultimately aim at learning about mechanisms of hadronic interaction.