Taste symmetry breaking with HYP-smeared staggered fermions

Abstract

We study the impact of hypercubic (HYP) smearing on the size of taste breaking for staggered fermions, comparing to unimproved and to asqtad-improved staggered fermions. As in previous studies, we find a substantial reduction in taste-breaking compared to unimproved staggered fermions (by a factor of 4-7 on lattices with spacing $a\approx 0.1$fm). In addition, we observe that discretization effects of next-to-leading order in the chiral expansion ($\mathcal{O}(a^2{p}^2)$) are markedly reduced by HYP smearing. Compared to asqtad valence fermions, we find that taste-breaking in the pion spectrum is reduced by a factor of 2.5-3, down to a level comparable to the expected size of generic $\mathcal{O}(a^2)$ effects. Our results suggest that, once one reaches a lattice spacing of $a\approx 0.09$fm, taste-breaking will be small enough after HYP smearing that one can use a modified power counting in which $\mathcal{O}(a^2)\ll \mathcal{O}(p^2)$, simplify fitting to phenomenologically interesting quantities.

14 pages, 13 figures, references updated, minor changes

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Cited by in corpus (11)

• $B_K$ using HYP-smeared staggered fermions in $N_f=2+1$ unquenched QCD
• Neutral kaon mixing from new physics: matrix elements in $N_f=2+1$ QCD
• Kaon $B$-parameter from improved staggered fermions in $N_f=2+1$ QCD
• Hadronic Screening in Improved Taste
• One-loop matching factors for staggered bilinear operators with improved gauge actions
• Taste non-Goldstone, flavor-charged pseudo-Goldstone boson masses in staggered chiral perturbation theory
• Calculating $B_K$ using HYP staggered fermions
• Statistical tweaks and flow scale from masses
• Chiral symmetry and taste symmetry from the eigenvalue spectrum of staggered Dirac operators
• Recent progress in staggered chiral perturbation theory
• Finite Volume Errors in $B_K$