Unquenching the Quark-Antiquark Green?s Function

Unquenching the Quark Model and Screened Potentials

Lattice gauge Wilson loop computations convincingly demonstrate that the interquark interaction grows linearly with distance. However, these computations are, somewhat paradoxically, made in the pure gauge theory: colour sources and sinks are taken to be static and virtual quarks are omitted. It is expected that the introduction of light quarks will allow the chromoelectric flux tube to break t...

Quark - Antiquark Bound

Asymmetric Quark/Antiquark Hadronization

We point out that the fragmentation of a strange quark into nucleons versus antinucleons is not necessarily identical Dp/s(z,Q ) 6= Dp/s(z,Q ), even though the perturbative contributions from gluon splitting and evolution are p ↔ p symmetric. The observation of such asymmetries in the hadronization of strange and other heavy quarks can provide insight into the nonperturbative mechanisms underly...

- quark - antiquark potential

We calculate the leading mass-suppressed two-loop contribution, proportional to αs/(mqr 2), to the potential of a heavy quark-antiquark system. This contribution originates in the nonabelian nature of quantum chromodynamics (QCD) and has no analogue in quantum electrodynamics (QED). For this purpose, we elaborate a technique based on the implementation of the threshold expansion within the effe...

Perturbative heavy quark-antiquark systems

In this review I cover recent developments concerning the construction of non-relativistic effective theories for perturbative heavy quark-antiquark systems and heavy quark mass definitions. I then discuss next-to-next-to-leading order results on quarkonium masses and decay, top quark pair production near threshold and QCD sum rules for Υ mesons. (November 1999, CERN-TH/99-355, hep-ph/9911490) ...