eta' meson From Two Flavor Dynamical Domain Wall Fermions

TL;DR

This study investigates the eta' meson spectrum in two-flavor lattice QCD using domain wall fermions, providing a lattice-based estimate of its mass and discussing systematic uncertainties.

Contribution

First lattice QCD calculation of eta' meson mass with domain wall fermions in two-flavor QCD, highlighting the relation between topology and the U(1)_A anomaly.

Findings

Estimated eta' mass: 819(127) MeV

Results support the topological origin of eta' mass

Discussion of systematic errors in lattice calculations

Abstract

We explore flavor singlet pseudoscalar meson, eta', spectrum in two-flavor (Nf=2) lattice QCD. The continuum-like relation between the topology of the QCD vacuum and the U(1)_A anomaly, that prevents eta' meson from being a would-be Nambu-Goldstone boson, are expected to hold in the domain wall fermions (DWF) used as a lattice quark field in this work. Although our simulation is limited to relatively heavy quark masses and statistical error is not magnificently small despite of improvements in measurements and fit procedures for meson propagators, we obtained m_eta'=819(127) MeV for Nf=2 QCD, where the error is statistical only. Potentially serious systematic error in the number are discussed. Results for other meson are also reported.