Matching Current Correlators in Lattice QCD to Chiral Perturbation Theory

TL;DR

This paper investigates the feasibility of extracting chiral Lagrangian couplings by fitting lattice QCD two-point correlators to chiral perturbation theory predictions, using advanced computational techniques and finite volume analysis.

Contribution

It introduces a method to determine chiral Lagrangian couplings from lattice QCD correlators with a novel finite volume regularization scheme.

Findings

Successful extraction of couplings from lattice data

Implementation of all-point quark propagators with pseudofermion technique

Analysis of finite volume effects using a new regularization scheme

Abstract

Chiral perturbation theory gives direct and unambiguous predictions for the form of various two-point hadronic correlators 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 correlators computed in lattice QCD to the predicted chiral form. The correlators 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 configurations 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.