Testing the fixed-point QCD action and the construction of chiral currents

TL;DR

This paper reports on quenched QCD measurements using a fixed-point Dirac operator, introduces a method for constructing chiral currents, and explores various physical observables related to chiral symmetry and topology.

Contribution

It provides the first quenched QCD results with the fixed-point Dirac operator and offers a practical construction of covariant densities and conserved chiral currents.

Findings

Successful measurement of hadron spectra and chiral deviations

Determination of the renormalized quark condensate and topological susceptibility

Analysis of eigenvalue distributions and local chirality of near-zero modes

Abstract

We present the first set of quenched QCD measurements using the recently parametrized fixed-point Dirac operator D^FP. We also give a general and practical construction of covariant densities and conserved currents for chiral lattice actions. The measurements include (a) hadron spectroscopy, (b) corrections of small chiral deviations, (c) the renormalized quark condensate from finite-size scaling and, independently, spectroscopy, (d) the topological susceptibility, (e) small eigenvalue distributions and random matrix theory, and (f) local chirality of near-zero modes and instanton-dominance.