One-loop matching factors for staggered bilinear operators with improved gauge actions

TL;DR

This paper calculates one-loop perturbative matching factors for bilinear operators with improved staggered fermions and various gluon actions, showing small reductions in corrections with improved gluon actions.

Contribution

It provides one-loop matching factors for improved staggered fermions with multiple gluon actions, extending previous calculations to include improved gauge actions.

Findings

Improved gluon actions slightly reduce perturbative corrections.

Reductions are smaller than those from fermion action improvements.

Results are relevant for electroweak matrix element calculations.

Abstract

We present results for one-loop perturbative matching factors using bilinear operators composed of improved staggered fermions, using unimproved (Wilson) and improved (Symanzik, Iwasaki, and DBW2) gluon actions. We consider two fermions actions---HYP/$\bar{\text{Fat7}}$-smeared and "asqtad". The former is being used in calculations of electroweak matrix elements, while the latter have been used extensively by the MILC collaboration. We observe that using the improved gluon action leads to small reductions in the perturbative corrections, but that these reductions are smaller than those obtained when moving from the tadpole-improved naive staggered action to either HYP-smeared or asqtad action.