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

Abstract

We compute the topological susceptibility of Nf = 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 ∼ 200 MeV up to ∼ 600 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.