Connections between lattice QCD and hadron phenomenology

Abstract

Lattice gauge theory is playing an increasingly important role in constraining quark-based models of hadron phenomenology. Toward that end, this paper summarizes lattice-based investigations of two fundamental QCD quantities, the gluon and quark propagators. We present a calculation of the gluon propagator using an O(a2) improved action with the corresponding O(a2) improved Landau gauge fixing. The gluon propagator obtained from the improved action and improved the Landau gauge condition is consistent with earlier unimproved results on similar lattice volumes of 3.23 × 6.4 fm4. This is then used to calculate the propagator on the very large volume of 5.63 × 11.2 fm4 and these results confirm the earlier conclusion that the Landau gauge gluon propagator is infrared finite. The quark propagator is calculated in Landau gauge at β = 6.0. A method for removing the dominant, tree-level lattice artefacts is presented, enabling a calculation of the momentum-dependent dynamical quark mass. In particular, the infrared quark mass is found to be 300 ± 30 MeV and the quark momentum-dependent wavefunction renormalization has the characteristic dip found in most Dyson-Schwinger-based quark model studies.