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Title: Discretization effects and the scalar meson correlator in mixed-action lattice simulations

Abstract

We study discretization effects in a mixed-action lattice theory with domain-wall valence quarks and Asqtad-improved staggered sea quarks. At the level of the chiral effective Lagrangian, discretization effects in the mixed-action theory give rise to two new parameters as compared to the lowest order Lagrangian for rooted-staggered fermions - the residual quark mass m{sub res} and the mixed valence-sea meson mass splitting {delta}{sub mix}. We find that m{sub res}, which parametrizes explicit chiral symmetry breaking in the mixed-action theory, is approximately one-quarter the size of our lightest valence quark mass on our coarser lattice spacing and of comparable size to that of simulations by the RBC and UKQCD Collaborations. We also find that the size of {delta}{sub mix} is comparable to the size of the smallest of the staggered meson taste splittings measured by the MILC Collaboration. Because lattice artifacts are different in the valence and sea sectors of the mixed-action theory, they give rise to unitarity-violating effects that disappear in the continuum limit, some of which should be described by mixed-action chiral perturbation theory (MA{chi}PT). Such effects are expected to be mild for many quantities of interest but are expected to be significant in the case of the isovectormore » scalar (a{sub 0}) correlator. Specifically, once the parameters m{sub res}, {delta}{sub mix}, and two others that can be determined from the light pseudoscalar meson spectrum are known, the two-particle intermediate state 'bubble' contribution to the scalar correlator is completely predicted within MA{chi}PT. We find that the behavior of the scalar meson correlator is quantitatively consistent with the MA{chi}PT prediction; this supports the claim that MA{chi}PT describes the dominant unitarity-violating effects in the mixed-action theory and can therefore be used to remove lattice artifacts and recover physical quantities.« less

Authors:
 [1];  [2];  [3]
  1. Department of Physics, College of William and Mary, Williamsburg, VA 23187 (United States)
  2. Physics Department, Washington University, St. Louis, MI 63130 (United States)
  3. Theoretical Physics Department, Fermilab, Batavia, IL 60510 (United States)
Publication Date:
OSTI Identifier:
21205092
Resource Type:
Journal Article
Journal Name:
Physical Review. D, Particles Fields
Additional Journal Information:
Journal Volume: 77; Journal Issue: 11; Other Information: DOI: 10.1103/PhysRevD.77.114501; (c) 2008 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0556-2821
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; CHIRAL SYMMETRY; CHIRALITY; COMPUTERIZED SIMULATION; FORECASTING; INTERMEDIATE STATE; ISOVECTORS; LAGRANGIAN FUNCTION; LATTICE FIELD THEORY; MASS; PERTURBATION THEORY; PSEUDOSCALAR MESONS; QUARKS; SCALAR MESONS; SPECTRA; SYMMETRY BREAKING; UNITARITY; VALENCE

Citation Formats

Aubin, C, Laiho, Jack, and Van de Water, Ruth S. Discretization effects and the scalar meson correlator in mixed-action lattice simulations. United States: N. p., 2008. Web. doi:10.1103/PHYSREVD.77.114501.
Aubin, C, Laiho, Jack, & Van de Water, Ruth S. Discretization effects and the scalar meson correlator in mixed-action lattice simulations. United States. https://doi.org/10.1103/PHYSREVD.77.114501
Aubin, C, Laiho, Jack, and Van de Water, Ruth S. 2008. "Discretization effects and the scalar meson correlator in mixed-action lattice simulations". United States. https://doi.org/10.1103/PHYSREVD.77.114501.
@article{osti_21205092,
title = {Discretization effects and the scalar meson correlator in mixed-action lattice simulations},
author = {Aubin, C and Laiho, Jack and Van de Water, Ruth S},
abstractNote = {We study discretization effects in a mixed-action lattice theory with domain-wall valence quarks and Asqtad-improved staggered sea quarks. At the level of the chiral effective Lagrangian, discretization effects in the mixed-action theory give rise to two new parameters as compared to the lowest order Lagrangian for rooted-staggered fermions - the residual quark mass m{sub res} and the mixed valence-sea meson mass splitting {delta}{sub mix}. We find that m{sub res}, which parametrizes explicit chiral symmetry breaking in the mixed-action theory, is approximately one-quarter the size of our lightest valence quark mass on our coarser lattice spacing and of comparable size to that of simulations by the RBC and UKQCD Collaborations. We also find that the size of {delta}{sub mix} is comparable to the size of the smallest of the staggered meson taste splittings measured by the MILC Collaboration. Because lattice artifacts are different in the valence and sea sectors of the mixed-action theory, they give rise to unitarity-violating effects that disappear in the continuum limit, some of which should be described by mixed-action chiral perturbation theory (MA{chi}PT). Such effects are expected to be mild for many quantities of interest but are expected to be significant in the case of the isovector scalar (a{sub 0}) correlator. Specifically, once the parameters m{sub res}, {delta}{sub mix}, and two others that can be determined from the light pseudoscalar meson spectrum are known, the two-particle intermediate state 'bubble' contribution to the scalar correlator is completely predicted within MA{chi}PT. We find that the behavior of the scalar meson correlator is quantitatively consistent with the MA{chi}PT prediction; this supports the claim that MA{chi}PT describes the dominant unitarity-violating effects in the mixed-action theory and can therefore be used to remove lattice artifacts and recover physical quantities.},
doi = {10.1103/PHYSREVD.77.114501},
url = {https://www.osti.gov/biblio/21205092}, journal = {Physical Review. D, Particles Fields},
issn = {0556-2821},
number = 11,
volume = 77,
place = {United States},
year = {Sun Jun 01 00:00:00 EDT 2008},
month = {Sun Jun 01 00:00:00 EDT 2008}
}