Flavour Singlet Mesons in Full QCD on the Lattice

TL;DR

This paper uses spectral methods on lattice QCD configurations to compute the eta' meson mass in the flavor singlet channel, providing evidence for a mass gap and setting the stage for more realistic simulations.

Contribution

It introduces a spectral method application to compute flavor singlet meson correlators in full QCD, demonstrating clear eta' mass plateau formation on the lattice.

Findings

Evidence of mass plateau in eta' channel

Detection of a persistent mass gap

First clear signal in this lattice setup

Abstract

We apply spectral methods to compute the OZI-rule suppressed loop-loop correlators in the pseudoscalar meson flavour singlet channel. Using SESAM configurations (obtained with two degenerate sea quark flavours on 16x16x16x32 lattices at beta = 5.6 with standard Wilson action), we find for the first time clear evidence for mass plateau formation in the eta' channel of this theory. As a consequence, we observe a clear signal of a mass gap persistent under chiral extrapolation. This sets the stage for a more realistic two-channel approach, where partially quenched strange quarks would be included, in addition to u, d sea quarks.