Two and three loops computations of renormalization constants for lattice QCD

TL;DR

This paper presents high-loop order calculations of renormalization constants in lattice QCD using Numerical Stochastic Perturbation Theory, including unquenched results and comparisons with non-perturbative methods.

Contribution

It introduces a method to compute renormalization constants at two and three loops in lattice QCD, extending previous perturbative approaches to unquenched scenarios.

Findings

Computed renormalization constants for Wilson fermions propagator.

Compared perturbative results with non-perturbative determinations.

Demonstrated feasibility of high-loop order calculations in unquenched lattice QCD.

Abstract

Renormalization constants can be computed by means of Numerical Stochastic Perturbation Theory to two/three loops in lattice perturbation theory, both in the quenched approximation and in the full (unquenched) theory. As a case of study we report on the computation of renormalization constants of the propagator for Wilson fermions. We present our unquenched (N_f=2) computations and compare the results with non perturbative determinations.