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arXiv · hep-lat/0610104

$B^0_s - \bar{B^0_s}$ Mixing Parameters from Unquenched Lattice QCD

Emel Dalgic·Alan Gray·Elvira Gamiz·Christine T. H. Davies·G. Peter Lepage·Junko Shigemitsu·Howard Trottier·Matthew Wingate
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Abstract

We determine hadronic matrix elements relevant for the mass and width differences, $ΔM_s$ & $ΔΓ_s$ in the $B^0_s - \bar{B^0_s}$ meson system using fully unquenched lattice QCD. We employ the MILC collaboration gauge configurations that include $u$, $d$ and $s$ sea quarks using the improved staggered quark (AsqTad) action and a highly improved gluon action. We implement the valence $s$ quark also with the AsqTad action and use Nonrelativistic QCD for the valence $b$ quark. For the nonperturbative QCD input into the Standard Model expression for $ΔM_s$ we find $f_{B_s} \sqrt{\hat{B}_{B_s}} = 0.281(21)$GeV. Results for four-fermion operator matrix elements entering Standard Model formulas for $ΔΓ_s$ are also presented.

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Emel Dalgic, Alan Gray, Elvira Gamiz, Christine T. H. Davies, G. Peter Lepage, Junko Shigemitsu, Howard Trottier, Matthew Wingate. 2007-06-21. $B^0_s - \bar{B^0_s}$ Mixing Parameters from Unquenched Lattice QCD. https://doi.org/10.1103/physrevd.76.011501

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