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arXiv · 1412.5097

Neutral B-meson mixing parameters in and beyond the SM with 2+1 flavor lattice QCD

C. M. Bouchard·E. D. Freeland·C. W. Bernard·C. C. Chang·A. X. El-Khadra·M. E. Gámiz·A. S. Kronfeld·J. Laiho·R. S. Van de Water
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Abstract

We report on the status of our calculation of the hadronic matrix elements for neutral $B$-meson mixing with asqtad sea and valence light quarks and using the Wilson clover action with the Fermilab interpretation for the $b$ quark. We calculate the matrix elements of all five local operators that contribute to neutral $B$-meson mixing both in and beyond the Standard Model. We use MILC ensembles with $N_f=2+1$ dynamical flavors at four different lattice spacings in the range $a \approx 0.045$--$0.12$~fm, and with light sea-quark masses as low as 0.05 times the physical strange quark mass. We perform a combined chiral-continuum extrapolation including the so-called wrong-spin contributions in simultaneous fits to the matrix elements of the five operators. We present a complete systematic error budget and conclude with an outlook for obtaining final results from this analysis.

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C. M. Bouchard, E. D. Freeland, C. W. Bernard, C. C. Chang, A. X. El-Khadra, M. E. Gámiz, A. S. Kronfeld, J. Laiho, R. S. Van de Water. 2014-12-16. Neutral B-meson mixing parameters in and beyond the SM with 2+1 flavor lattice QCD. https://arxiv.org/abs/1412.5097

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