The eta ' signal from partially quenched Wilson fermions

TL;DR

This paper investigates the eta' signal in partially quenched Wilson fermions using eigenmode expansions and ground state contributions, revealing persistent early mass plateauing in the eta' channel.

Contribution

It introduces an improved computational approach with even-odd preconditioning and extends previous eta' mass plateau findings to partially quenched QCD.

Findings

Early mass plateauing persists in the eta' channel under partial quenching.

Eigenmode expansion and ground state incorporation enhance computation accuracy.

Method improvements lead to better understanding of flavor singlet pseudoscalar mesons.

Abstract

We present new results from our ongoing study of flavor singlet pseudoscalar mesons in QCD. Our approach is based on (a) performing truncated eigenmode expansions for the hairpin diagram and (b) incorporating the ground state contribution for the connected meson propagator. First, we explain how the computations can be substantially improved by even-odd preconditioning. We extend previous results on early mass plateauing in the eta' channel of two-flavor full QCD with degenerate sea and valence quarks to the partially quenched situation. We find that early mass plateau formation persists in the partially quenched situation.