skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Unquenched determination of the kaon parameter B{sub K} from improved staggered fermions

Abstract

The use of improved staggered actions (HYP, Asqtad) has been proved to reduce the scaling corrections that affected previous calculations of B{sub K} with unimproved (standard) staggered fermions in the quenched approximation. This improved behavior allows us to perform a reliable calculation of B{sub K} including quark vacuum polarization effects, using the MILC configurations with n{sub f}=2+1 flavors of sea fermions. We perform such a calculation for a single lattice spacing, a=0.125 fm, and with kaons made up of degenerate quarks with m{sub s}/2. The valence strange quark mass m{sub s} is fixed to its physical value and we use two different values of the light sea quark masses. After a chiral extrapolation of the results to the physical value of the sea quark masses, we find B-circumflex{sub K}=0.83{+-}0.18, where the error is dominated by the uncertainty in the lattice to continuum matching at O({alpha}{sub s}{sup 2}). The matching will need to be improved to get the precision needed to make full use of the experimental data on {epsilon}{sub K} to constrain the unitarity triangle.

Authors:
; ; ; ; ;  [1]
  1. Department of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ (United Kingdom)
Publication Date:
OSTI Identifier:
20774817
Resource Type:
Journal Article
Journal Name:
Physical Review. D, Particles Fields
Additional Journal Information:
Journal Volume: 73; Journal Issue: 11; Other Information: DOI: 10.1103/PhysRevD.73.114502; (c) 2006 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; ACCURACY; APPROXIMATIONS; CHIRALITY; CORRECTIONS; EXTRAPOLATION; KAONS; REST MASS; S QUARKS; UNITARITY; VACUUM POLARIZATION; VALENCE

Citation Formats

Gamiz, Elvira, Collins, Sara, Davies, Christine T.H., Lepage, G Peter, Shigemitsu, Junko, Wingate, Matthew, Laboratory of Elementary-Particle Physics, Cornell University, Ithaca, New York 14853, Physics Department, Ohio State University, Columbus, Ohio 43210, and Institute for Nuclear Theory, University of Washington, Seattle, Washington 98115. Unquenched determination of the kaon parameter B{sub K} from improved staggered fermions. United States: N. p., 2006. Web. doi:10.1103/PhysRevD.73.114502.
Gamiz, Elvira, Collins, Sara, Davies, Christine T.H., Lepage, G Peter, Shigemitsu, Junko, Wingate, Matthew, Laboratory of Elementary-Particle Physics, Cornell University, Ithaca, New York 14853, Physics Department, Ohio State University, Columbus, Ohio 43210, & Institute for Nuclear Theory, University of Washington, Seattle, Washington 98115. Unquenched determination of the kaon parameter B{sub K} from improved staggered fermions. United States. https://doi.org/10.1103/PhysRevD.73.114502
Gamiz, Elvira, Collins, Sara, Davies, Christine T.H., Lepage, G Peter, Shigemitsu, Junko, Wingate, Matthew, Laboratory of Elementary-Particle Physics, Cornell University, Ithaca, New York 14853, Physics Department, Ohio State University, Columbus, Ohio 43210, and Institute for Nuclear Theory, University of Washington, Seattle, Washington 98115. 2006. "Unquenched determination of the kaon parameter B{sub K} from improved staggered fermions". United States. https://doi.org/10.1103/PhysRevD.73.114502.
@article{osti_20774817,
title = {Unquenched determination of the kaon parameter B{sub K} from improved staggered fermions},
author = {Gamiz, Elvira and Collins, Sara and Davies, Christine T.H. and Lepage, G Peter and Shigemitsu, Junko and Wingate, Matthew and Laboratory of Elementary-Particle Physics, Cornell University, Ithaca, New York 14853 and Physics Department, Ohio State University, Columbus, Ohio 43210 and Institute for Nuclear Theory, University of Washington, Seattle, Washington 98115},
abstractNote = {The use of improved staggered actions (HYP, Asqtad) has been proved to reduce the scaling corrections that affected previous calculations of B{sub K} with unimproved (standard) staggered fermions in the quenched approximation. This improved behavior allows us to perform a reliable calculation of B{sub K} including quark vacuum polarization effects, using the MILC configurations with n{sub f}=2+1 flavors of sea fermions. We perform such a calculation for a single lattice spacing, a=0.125 fm, and with kaons made up of degenerate quarks with m{sub s}/2. The valence strange quark mass m{sub s} is fixed to its physical value and we use two different values of the light sea quark masses. After a chiral extrapolation of the results to the physical value of the sea quark masses, we find B-circumflex{sub K}=0.83{+-}0.18, where the error is dominated by the uncertainty in the lattice to continuum matching at O({alpha}{sub s}{sup 2}). The matching will need to be improved to get the precision needed to make full use of the experimental data on {epsilon}{sub K} to constrain the unitarity triangle.},
doi = {10.1103/PhysRevD.73.114502},
url = {https://www.osti.gov/biblio/20774817}, journal = {Physical Review. D, Particles Fields},
issn = {0556-2821},
number = 11,
volume = 73,
place = {United States},
year = {Thu Jun 01 00:00:00 EDT 2006},
month = {Thu Jun 01 00:00:00 EDT 2006}
}