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Measurement of the $B_{s}^{0} \rightarrow D_{s}^{(*)+}D_{s}^{(*)-}$ branching fractions

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Abstract

The branching fraction of the decay $B_{s}^{0} \rightarrow D_{s}^{(*)+}D_{s}^{(*)-}$ is measured using $pp$ collision data corresponding to an integrated luminosity of $1.0fb^{-1}$, collected using the LHCb detector at a centre-of-mass energy of $7$TeV. It is found to be \begin{align*} {\mathcal{B}}(B_{s}^{0}\rightarrow D_{s}^{(*)+}D_{s}^{(*)-}) = (3.05 \pm 0.10 \pm 0.20 \pm 0.34)\%, \end{align*} where the uncertainties are statistical, systematic, and due to the normalisation channel, respectively. The branching fractions of the individual decays corresponding to the presence of one or two $D^{*\pm}_{s}$ are also measured. The individual branching fractions are found to be \begin{align*} {\mathcal{B}}(B_{s}^{0}\rightarrow D_{s}^{*\pm}D_{s}^{\mp}) = (1.35 \pm 0.06 \pm 0.09 \pm 0.15)\%, \newline{\mathcal{B}}(B_{s}^{0}\rightarrow D_{s}^{*+}D_{s}^{*-}) = (1.27 \pm 0.08 \pm 0.10 \pm 0.14)\%. \end{align*} All three results are the most precise determinations to date.

Figures and captions

Invariant mass distribution of the $ B ^0_ s \rightarrow D ^{(*)+}_ s D ^{(*)-}_ s $ candidates. Also shown is the fit function and the individual components of the fit model.

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Invariant mass distribution of the $ { B ^0 \rightarrow D^{(*)\pm}_{s} D_{}^{(*)\mp}}$ candidates. Also shown is the fit function and the individual components of the fit model.

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The $ B ^0_ s \rightarrow D ^{(*)+}_ s D ^{(*)-}_ s $ branching fraction measurements by Belle , CDF , and D0 , the current world average, the theoretical prediction from Ref. [3], and the new LHCb result.

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Animated gif made out of all figures.

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Tables and captions

Efficiencies of the various selection criteria for the three individual channels of $ B ^0_ s \rightarrow D ^{(*)+}_ s D ^{(*)-}_ s $ , and for $ B ^0 \rightarrow D ^+_ s D ^- $. Each efficiency is presented relative to the previous cut and measured using simulated events, except for the PID efficiency which is obtained from data. The $ D ^+_ s $ veto was only applied to the normalisation mode, $ B ^0 \rightarrow D ^+_ s D ^- $.

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Efficiency of the normalisation channel $ B ^0 \rightarrow D ^+_ s D ^- $ relative to the signal decays.

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The yields extracted from the fit to the $ B ^0_ s \rightarrow D ^{(*)+}_ s D ^{(*)-}_ s $ candidate sample.

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The yields extracted from the fit to the $ { B ^0 \rightarrow D^{(*)\pm}_{s} D_{}^{(*)\mp}}$ candidate sample.

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Systematic uncertainties, in % of the relevant branching fraction ratio, for the $ B ^0_ s \rightarrow D ^{(*)+}_ s D ^{(*)-}_ s $ branching fraction ratios.

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Created on 09 December 2018.Citation count from INSPIRE on 09 December 2018.