Probing the QCD vacuum with flavour singlet objects: $\eta'$ on the lattice

TL;DR

This paper investigates the mass of the $ ext{η'}$ meson in lattice QCD using configurations with two flavors of Wilson fermions, revealing a dependence on topological charge sectors.

Contribution

It provides a direct lattice QCD determination of the $ ext{η'}$ mass and explores its relation to topological charge sectors.

Findings

The $ ext{η'}$ mass shows a clear dependence on topological charge sectors.

The study uses SESAM and T$ ext{χ}$L configurations at $eta=5.6$.

Two-loop correlator analysis reveals sector-dependent behavior.

Abstract

We present a study on the direct determination of the $\eta '$ mass on the full set of SESAM and T$\chi$L QCD vacuum configurations with 2 active flavours of Wilson fermions, at $\beta = 5.6$. We observe a definite dependency of the two-loop correlator on the topological charge sector.