Matching current correlators in lattice QCD to chiral perturbation theory
Chiral perturbation theory gives direct and unambiguous predictions for the form of various two-point hadronic correlates at low momentum in terms of a finite set of couplings in a chiral Lagrangian. In this paper we study the feasibility of extracting the couplings in the chiral Lagrangian (through 1-loop order) by fitting two-point correlates computed in lattice QCD to the predicted chiral form. The correlates are computed using a pseudofermion technique yielding all-point quark propagators which allows the computation of the full four-momentum transform of the two-point functions to be obtained without sacrificing any of the physical content of the unquenched gauge config-urations used. Results are given for an ensemble of dynamical configurations generated using the truncated determinant algorithm on a large coarse lattice. We also present a new analysis of finite volume effects based on a finite volume dimensional regularization scheme which preserves the power-counting rules appropriate for a chiral Lagrangian.