Testing chiral effective theory with quenched lattice QCD

TL;DR

This study compares quenched lattice QCD results with quenched chiral perturbation theory predictions across different regimes, confirming leading order behavior but not sufficiently precise for next-to-leading order tests.

Contribution

It provides a detailed comparison of lattice QCD data with chiral perturbation theory in the quenched approximation, testing effective theory predictions at leading order.

Findings

Leading order predictions match lattice data well.

Data insufficient to test next-to-leading order effects.

Volume and quark mass dependence analyzed in different regimes.

Abstract

We investigate two-point correlation functions of left-handed currents computed in quenched lattice QCD with the Neuberger-Dirac operator. We consider two lattice spacings a~0.09,0.12 fm and two different lattice extents L~ 1.5, 2.0 fm; quark masses span both the p- and the epsilon-regimes. We compare the results with the predictions of quenched chiral perturbation theory, with the purpose of testing to what extent the effective theory reproduces quenched QCD at low energy. In the p-regime we test volume and quark mass dependence of the pseudoscalar decay constant and mass; in the epsilon-regime, we investigate volume and topology dependence of the correlators. While the leading order behaviour predicted by the effective theory is very well reproduced by the lattice data in the range of parameters that we explored, our numerical data are not precise enough to test next-to-leading order effects.