Renormalization constants of quark bilinear operators in QCD with dynamical up, down, strange and charm quarks

TL;DR

This paper reports a non-perturbative lattice calculation of QCD renormalization constants for quark bilinear operators using a dedicated $N_f=4$ twisted mass fermion ensemble, emphasizing systematic error control for precise phenomenological results.

Contribution

It provides a detailed analysis of systematic errors and scaling behavior in the non-perturbative calculation of RCs in the RI'-MOM scheme with $N_f=4$ dynamical quarks.

Findings

High statistical precision in RC calculations achieved.

Careful control of hadronic contaminations and systematic errors.

Results suitable for accurate quark mass phenomenology.

Abstract

We present preliminary results of a calculation of the QCD renormalization constants (RCs) for quark bilinear operators, evaluated non-perturbatively on the lattice in the RI'-MOM scheme. The calculation is performed by using dedicated ensembles with $N_f=4$ degenerate dynamical twisted mass (clover) fermions and the Iwasaki gauge action. A detailed analysis is reported, with emphasis on the control or subtraction of the hadronic contaminations occurring in the lattice estimators of RCs and a check of proper scaling with $a^2$ of the final results. Such a careful study of systematic errors is the counterpart of the high statistical precision reached by current calculations of RCs in the RI'-MOM scheme and is important in order to quote accurate results in phenomenological applications, such as the computation of quark masses.