Scaling behavior and sea quark dependence of pion spectrum with HYP-smeared staggered fermions

TL;DR

This study investigates the pion spectrum and taste-symmetry breaking effects using HYP-smeared staggered fermions on MILC lattices, highlighting the impact of lattice spacing and sea-quark mass on discretization errors.

Contribution

It provides new insights into the discretization errors in staggered chiral perturbation theory, especially on fine lattices, and updates on source dependence effects.

Findings

Discretization errors may enter at next-to-leading order on fine lattices.

Taste-symmetry breaking effects are analyzed with HYP-smeared fermions.

Results inform power-counting schemes in staggered chiral perturbation theory.

Abstract

We study the pion spectrum (and in particular taste-symmetry breaking within it) using HYP-smeared valence staggered fermions on the coarse and fine MILC lattices (which have asqtad staggered sea quarks). We focus on the dependence on lattice spacing and sea-quark mass. We also update our results on source dependence. Our main conclusion is that on the MILC fine lattices the appropriate power-counting for SU(3) staggered chiral perturbation theory may have discretization errors entering at next-to-leading order rather than at leading-order.