Non-perturbative renormalization for general improved staggered bilinears

TL;DR

This paper develops a non-perturbative method to calculate renormalization factors for staggered fermion bilinears, improving accuracy by avoiding mixing and comparing results with perturbation theory.

Contribution

It introduces covariant bilinears that transform irreducibly, enabling precise non-perturbative renormalization for arbitrary spin and taste staggered bilinears.

Findings

NPR factors for staggered bilinears are computed and compared to 1-loop perturbation theory.

Covariant bilinears do not mix under lattice symmetries, simplifying renormalization.

Results show good agreement between NPR and perturbative calculations for certain ratios.

Abstract

We present results for non-perturbative renormalization (NPR) factors for staggered fermion bilinears of arbitrary spin and taste. We use "covariant" bilinears which transform irreducibly under the lattice translation and rotation group, and thus do not mix. We form ~ 30 ratios which have no anomalous dimensions, and compare the NPR results to those from 1-loop perturbation theory. We also compare the absolute renormalization factors (which, in general, do have anomalous dimensions) to 1-loop perturbation theory. We use asqtad and HYP-smeared staggered valence fermions on the coarse MILC asqtad lattices.