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arXiv · 1010.4779

$B_K$ with improved staggered fermions: analysis using SU(3) staggered chiral perturbation theory

Jangho Kim·Taegil Bae·Yong-Chull Jang·Hyung-Jin Kim·Jongjeong Kim·Kwangwoo Kim·Boram Yoon·Weonjong Lee·Chulwoo Jung·Stephen R. Sharpe
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Abstract

We report updated results for $B_K$ using HYP-smeared staggered valence quarks on MILC asqtad lattices based on an analysis using SU(3) staggered chiral perturbation theory. The most important new feature of our data sample is the inclusion of a fourth ("ultrafine") lattice spacing. This improves the control over the continuum extrapolation and errors due our use of one-loop perturbative matching. We present a complete updated error budget, which leads to $B_K(\text{NDR}, μ= 2 \text{GeV}) = 0.5309 \pm 0.0051 \pm 0.0424$ and $\hat{B}_K = B_K(\text{RGI}) = 0.727 \pm 0.07 \pm 0.058$. The results of the SU(3) analysis are inferior to those based on SU(2) staggered chiral perturbation theory, primarily because of the dependence on the Bayesian priors we use in the SU(3) fits.

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Jangho Kim, Taegil Bae, Yong-Chull Jang, Hyung-Jin Kim, Jongjeong Kim, Kwangwoo Kim, Boram Yoon, Weonjong Lee, Chulwoo Jung, Stephen R. Sharpe. 2010-10-28. $B_K$ with improved staggered fermions: analysis using SU(3) staggered chiral perturbation theory. https://arxiv.org/abs/1010.4779

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