Topological susceptibility of $N_f=2+1$ QCD from staggered fermions spectral projectors at high temperatures

TL;DR

This study calculates the topological susceptibility of $N_f=2+1$ QCD at high temperatures using spectral projectors with staggered fermions, reducing lattice artifacts and enabling reliable continuum extrapolation.

Contribution

It introduces a spectral projector method with staggered fermions for more accurate topological susceptibility measurements at high temperatures.

Findings

Susceptibility estimates for 200-600 MeV temperatures.

Reduction of lattice artifacts compared to gluonic definitions.

Partial tension with previous literature results.

Abstract

We compute the topological susceptibility of $N_f=2+1$ QCD with physical quark masses in the high-temperature phase, using numerical simulations of the theory discretized on a space-time lattice. More precisely we estimate the topological susceptibility for five temperatures in the range from $\sim200$ MeV up to $\sim600$ MeV, adopting the spectral projectors definition of the topological charge based on the staggered Dirac operator. This strategy turns out to be effective in reducing the large lattice artifacts which affect the standard gluonic definition, making it possible to perform a reliable continuum extrapolation. Our results for the susceptibility in the explored temperature range are found to be partially in tension with previous determinations in the literature.