Topological Susceptibility in Two Flavors Lattice QCD with the Optimal Domain-Wall Fermion

TL;DR

This study calculates the topological susceptibility in two-flavor lattice QCD using optimal domain-wall fermions, confirming theoretical predictions and extracting key physical constants like the chiral condensate and pion decay constant.

Contribution

It provides a novel lattice QCD calculation of topological susceptibility with optimal domain-wall fermions, aligning with chiral perturbation theory and determining fundamental QCD parameters.

Findings

Topological susceptibility agrees with chiral perturbation theory predictions.

Determined the chiral condensate as [259(6)(7) MeV]^3.

Estimated the pion decay constant as 92(12)(2) MeV.

Abstract

We determine the topological susceptibility of the gauge configurations generated by lattice simulations using two flavors of optimal domain-wall fermion on the $ 16^3 \times 32 $ lattice with length 16 in the fifth dimension, at the lattice spacing $ a \simeq 0.1 $ fm. Using the adaptive thick-restart Lanczos algorithm, we project the low-lying eigenmodes of the overlap Dirac operator, and obtain the topological charge of each configuration, for eight ensembles with pion masses in the range $ 220-550 $ MeV. From the topological charge, we compute the topological susceptibility and the second normalized cumulant. Our result of the topological susceptibility agrees with the sea-quark mass dependence predicted by the chiral perturbation theory and provides a determination of the chiral condensate, $\Sigma^{\bar{MS}}(2 GeV)=[259(6)(7) MeV]^3 $, and the pion decay constant $F_\pi = 92(12)(2)$ MeV.