Topological susceptibility in 2+1-flavor QCD with chiral fermions

TL;DR

This study calculates the topological susceptibility in 2+1-flavor lattice QCD with chiral fermions, confirming theoretical predictions and extracting the chiral condensate at the physical point.

Contribution

First computation of topological susceptibility in 2+1-flavor lattice QCD using M"obius domain-wall fermions with residual mass below 1 MeV, employing the slab method for analysis.

Findings

Results agree with chiral perturbation theory predictions.

Extracted the chiral condensate at the physical point.

Provided a precise value of topological susceptibility in lattice QCD.

Abstract

We compute the topological susceptibility $\chi_t$ of 2+1-flavor lattice QCD with dynamical M\"obius domain-wall fermions, whose residual mass is kept at 1 MeV or smaller. In our analysis, we focus on the fluctuation of the topological charge density in a "slab" sub-volume of the simulated lattice, as proposed by Bietenholz et al. The quark mass dependence of our results agrees well with the prediction of the chiral perturbation theory, from which the chiral condensate is extracted. Combining the results for the pion mass $M_\pi$ and decay constant $F_\pi$, we obtain $\chi_t$ = 0.227(02)(11)$M_\pi^2 F_\pi^2$ at the physical point, where the first error is statistical and the second is systematic.