Pseudoscalar singlet physics with staggered fermions

TL;DR

This paper discusses progress in measuring disconnected correlators for pseudoscalar flavor-singlet mesons using staggered fermions, aiming to compute eta and eta' masses and test lattice QCD methods.

Contribution

It introduces new measurements of disconnected correlators with staggered fermions to study flavor-singlet mesons and evaluate the validity of the fourth-root trick in lattice QCD.

Findings

Progress in measuring disconnected correlators for pseudoscalar mesons.

Potential to compute eta and eta' meson masses.

Tests of staggered fermion formulation and the fourth-root trick.

Abstract

We report on progress in measuring disconnected correlators associated with pseudoscalar flavor-singlet mesons. This will eventually allow us to compute the masses of the eta and eta' mesons. Flavor-singlet physics also presents an interesting test of the staggered fermion formulation, as disconnected correlators are sensitive to whether the same action governs both sea quarks and valence quarks. It can also help test the validity of the ``fourth-root trick'' used in unquenched lattice calculations where the number of flavors $N_f<4$.