Non-perturbative renormalization of flavor singlet quark bilinear operators in lattice QCD

TL;DR

This paper presents a non-perturbative method to determine renormalization constants for flavor singlet quark bilinear operators in lattice QCD, addressing the disconnected contributions and comparing results with perturbation theory.

Contribution

It introduces a non-perturbative approach to renormalize flavor singlet operators in lattice QCD, including stochastic estimation of disconnected diagrams.

Findings

Renormalization constants determined non-perturbatively in RI'-MOM scheme

Disconnected contributions evaluated using stochastic estimators

Comparison shows agreement with perturbative running at high energies

Abstract

We report on our studies of the renormalization of flavor singlet quark bilinear operators in lattice QCD. The renormalization constants are determined non-perturbatively using gauge field ensembles with Nf=2 dynamical clover improved fermions. The renormalization is performed in the RI'-MOM scheme. The difference between flavor singlet and non-singlet quark bilinear operators is a disconnected contribution, which has to be evaluated by stochastic estimators. We compare our results for the running with perturbation theory.