First results from 2+1-Flavor Domain Wall QCD: Mass Spectrum, Topology Change and Chiral Symmetry with $L_s=8$

TL;DR

This paper reports initial results from 2+1-flavor domain wall QCD simulations, analyzing the mass spectrum, topology, and chiral symmetry, demonstrating the feasibility of generating realistic QCD ensembles with specific lattice parameters.

Contribution

It introduces the first results from 2+1-flavor domain wall QCD simulations using different gauge actions, assessing chiral symmetry and topological properties at lattice spacings above 0.1 fm.

Findings

Iwasaki gauge action performs best for these simulations.

Results for light hadronic physics agree with experimental data.

Feasibility of generating large-scale QCD ensembles with desired properties.

Abstract

We present results for the static interquark potential, light meson and baryon masses, and light pseudoscalar meson decay constants obtained from simulations of domain wall QCD with one dynamical flavour approximating the $s$ quark, and two degenerate dynamical flavours with input bare masses ranging from $m_s$ to $m_s/4$ approximating the $u$ and $d$ quarks. We compare these quantities obtained using the Iwasaki and DBW2 improved gauge actions, and actions with larger rectangle coefficients, on $16^3\times32$ lattices. We seek parameter values at which both the chiral symmetry breaking residual mass due to the finite lattice extent in the fifth dimension and the Monte Carlo time history for topological charge are acceptable for this set of quark masses at lattice spacings above 0.1 fm. We find that the Iwasaki gauge action is best, demonstrating the feasibility of using QCDOC to generate ensembles which are good representations of the QCD path integral on lattices of up to 3 fm in spatial extent with lattice spacings in the range 0.09-0.13 fm. Despite large residual masses and a limited number of sea quark mass values with which to perform chiral extrapolations, our results for light hadronic physics scale and agree with experimental measurements within our statistical uncertainties.