Armin Wachter

Complete O (v**2) corrections to the static interquark potential from SU(3) gauge theory

For the first time, we determine the complete spin- and momentum-dependent order v{sup 2} corrections to the static interquark potential from simulations of QCD in the valence quark approximation at inverse lattice spacings of 2{endash}3 GeV. A new flavor-dependent correction to the central potential is found. We report an r{sup {minus}2} contribution to the long range spin-orbit potential V{sub 1}{sup {prime}}. The other spin-dependent potentials turn out to be short ranged and can be well understood by means of perturbation theory. The momentum-dependent potentials qualitatively agree with minimal area law expectations. In view of spectrum calculations, we discuss the matching of the effective nonrelativistic theory to QCD as well as renormalization of lattice results. In a first survey of the resulting bottomonia and charmonia spectra we reproduce the experimental levels within average errors of 12.5 MeV and 22 MeV, respectively. {copyright} {ital 1997} {ital The American Physical Society}

{bold {ital Ab initio}} calculation of relativistic corrections to the static interquark potential: SU(2) gauge theory

We test the capability of state-of-the-art lattice techniques for a precise determination of relativistic corrections to the static interquark potential by use of SU(2) gauge theory. Emphasis is put on the short-range structure of the spin-dependent potentials, with the lattice resolution a ranging from a{approx}0.04fm (at {beta}=2.74) down to a{approx}0.02fm (at {beta}=2.96) on volumes of 32{sup 4} and 48{sup 4} lattice sites. We find a new Coulomb-like contribution to the long-range spin-orbit potential V{sub 1}{sup {prime}}. {copyright} {ital 1997} {ital The American Physical Society}

The static potential in full QCD: a precise determination☆

Abstract We present a lattice calculation of the interquark potential between static quarks in a “full” QCD simulation with 2 flavours of dynamical Wilson-quarks at three intermediate sea-quark masses. We work at β = 5.6 on a lattice size of 163 × 32 with 100 configurations per sea-quark mass. We compare the full QCD potential with its quenched counterpart at equal lattice spacing, a −1 ⋍ 2.0 GeV , which is at the onset of the quenched scaling regime. We find that the full QCD potential lies consistently below that of quenched QCD. We see no evidence for string-breaking effects on these lattice volumes, V ⋍ (1.5 fm ) 3 .

QUARK-ANTIQUARK FORCES FROM SU(2) AND SU(3) GAUGE THEORIES ON LARGE LATTICES

We present results on the spin-independent quark-antiquark potential in SU(3) gauge theory from a simulation on a 48^3*64 lattice at Beta = 6.8, corresponding to a volume of (1.7 fm)^3. Moreover, a comprehensive analysis of spin- and velocity-dependent potentials is carried out for SU(2) gauge theory, with emphasis on the short range structure, on lattices with resolutions ranging from .02 fm to .04 fm.

Statistische Physik und Thermodynamik

Das Fundament der theoretischen Beschreibung makroskopischer Systeme (Gase, Flussigkeiten und Festkorper) in der heute vorliegenden Form wurde vor etwa 200 Jahren gelegt. Die damals und in der Folgezeit von Rumford, Davy, Mayer, Joule u.v.a. empirisch gefundenen Gesetze bilden auch heute noch die Grundlage der Thermodynamik, welche durch Lord Kelvin 1850 erstmals in konsistenter Darstellung formuliert wurde. Etwa um diese Zeit begann sich die Meinung durchzusetzen, das Materie Substrukur in Form von Atomen und Molekulen besitzt, und man fing an, makroskopische Systeme mikroskopisch zu untersuchen. Die Entwicklung der Quantenmechanik in den 20er Jahren dieses Jahrhunderts lieferte schlieslich den adaquaten Rahmen fur eine realistische mikroskopische Beschreibung solcher Systeme.

Relativistic corrections to the central qq potential from pure SU(3) lattice gauge theory

Abstract We present a comprehensive high statistics analysis of spin- and velocity dependent corrections to the static (central) q q potential in pure SU(3) lattice gauge theory. Simulations have been performed at β = 6.0 and β = 6.2 which corresponds to tattice spacings of 0.1 and 0.07 fm.

Spin dependent potentials from SU(2) gauge theory

We present results on spin dependent potentials from lattice simulations of SU (2) gauge theory. The Coulomb like short range part of the central potential is identified as a mixed vector-scalar exchange while the linear long range part is pure scalar.