Flavor symmetry breaking and scaling for improved staggered actions in quenched QCD

TL;DR

This paper investigates flavor symmetry breaking in the pion spectrum of various improved staggered fermion actions in quenched QCD, comparing different link smearing and tadpole improvement techniques across multiple lattice spacings.

Contribution

It provides a comparative analysis of flavor symmetry breaking patterns for several improved staggered actions using comprehensive meson mass measurements.

Findings

Reduced flavor symmetry breaking with improved actions

Quantitative comparison of different link smearing techniques

Insights into lattice scale setting using rho mass and static potential

Abstract

We present a study of the flavor symmetry breaking in the pion spectrum for various improved staggered fermion actions. To study the effects of link fattening and tadpole improvement, we use three different variants of the p4 action - p4fat3, p4fat7, and p4fat7tad. These are compared to Asqtad and also to naive staggered. To study the pattern of symmetry breaking, we measure all 15 meson masses in the 4-flavor staggered theory. The measurements are done on a quenched gauge background, generated using a one-loop improved Symanzik action with $\beta=10/g^2 = 7.40, 7.75,$ and 8.00, corresponding to lattice spacings of approximately a = .31 fm., .21 fm., and .14 fm. We also study how the lattice scale set by the $\rho$ mass on each of these ensembles compares to one set by the static quark potential.