One-loop matching coefficients for improved staggered bilinears

TL;DR

This paper computes one-loop matching factors for improved staggered fermion bilinear operators, showing that various smearing schemes significantly reduce discretization errors and improve matching accuracy.

Contribution

It provides a detailed comparison of different improvement schemes for staggered fermions, quantifying their effectiveness in reducing matching corrections.

Findings

All improvement schemes reduce matching factors compared to unimproved staggered fermions.

Corrections are comparable to those with Wilson and domain-wall fermions.

Best schemes achieve corrections of 10% or smaller at 1/a = 2 GeV.

Abstract

We calculate one-loop matching factors for bilinear operators composed of improved staggered fermions. We compare the results for different improvement schemes used in the recent literature, all of which involve the use of smeared links. These schemes aim to reduce, though not completely eliminate, O(a^2) discretization errors. We find that all these improvement schemes substantially reduce the size of matching factors compared to unimproved staggered fermions. The resulting corrections are comparable to, or smaller than, those found with Wilson and domain-wall fermions. In the best case (``Fat-7'' and mean-field improved HYP links) the corrections are 10 % or smaller at 1/a = 2 GeV.