Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Penguin contribution to width difference and CP asymmetry in $B_q$-$\bar
  B_q$ mixing at order $\alpha_s^2 N_f$   We present new contributions to the decay matrix element $\Gamma_{12}^q$ of
the $B_q$-$\bar B_q$ mixing complex, where $q=d$ or $s$. Our new results
constitute the order $\alpha_s^2 N_f$ corrections to the penguin contributions
to the Wilson coefficients entering $\Gamma_{12}^q$ with full dependence on the
charm quark mass. This is the first step towards the prediction of the CP
asymmetry $a_{\rm fs}^q$ quantifying CP violation in mixing at
next-to-next-to-leading logarithmic order (NNLO) in quantum chromodynamics
(QCD) and further improves the prediction of the width difference
$\Delta\Gamma_q$ between the two neutral-meson eigenstates. We find a sizable
effect from the non-zero charm mass and our partial NNLO result decreases the
NLO penguin corrections to $a_{\rm fs}^q$ by 37\% and those to $\Delta\Gamma_q$
by 16\%. We further update the Standard-Model NLO predictions for $a_{\rm
fs}^q$ and the ratio of the width and mass differences of the $B_q$
eigenstates: If we express the results in terms of the pole mass of the bottom
quark we find $a_{\rm fs}^s=(2.07 \pm 0.10)\cdot 10^{-5}$, $a_{\rm fs}^d=(-4.71
\pm 0.24)\cdot 10^{-4}$, $\Delta{\Gamma}_s/\Delta{M}_s = (4.33 \pm 1.26)\cdot
10^{-3}$, and $\Delta{\Gamma}_d/\Delta{M}_d = (4.48 \pm 1.19)\cdot 10^{-3}$. In
the $\overline{\rm MS}$ scheme these numbers read $a^s_{\rm fs} =(2.04 \pm
0.11)\cdot 10^{-5}$, $a^d_{\rm fs} = (-4.64 \pm 0.25)\cdot 10^{-4}$,
$\Delta{\Gamma}_s/\Delta{M}_s = (4.97 \pm 1.02)\cdot 10^{-3}$, and
$\Delta{\Gamma}_d/\Delta{M}_d = (5.07 \pm 0.96)\cdot 10^{-3}$.

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The categories of this paper are: math-ph
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The categories of this paper are: supr-con
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The categories of this paper are: comp-gas
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ex
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The categories of this paper are: plasm-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: astro-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: funct-an
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The categories of this paper are: solv-int
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The categories of this paper are: quant-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: physics
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The categories of this paper are: econ
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The categories of this paper are: stat