# 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. Fig1.pdf [43 KiB] HiDef png [856 KiB] Thumbnail [341 KiB] *.C file % 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. Fig2.pdf [46 KiB] HiDef png [604 KiB] Thumbnail [291 KiB] *.C file % 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. Fig3.pdf [13 KiB] HiDef png [83 KiB] Thumbnail [82 KiB] *.C file Animated gif made out of all figures. PAPER-2015-053.gif Thumbnail

## 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, $B ^0 \rightarrow D ^+_ s D ^-$. Table_1.pdf [54 KiB] HiDef png [118 KiB] Thumbnail [55 KiB] tex code % Efficiency of the normalisation channel $B ^0 \rightarrow D ^+_ s D ^-$ relative to the signal decays. Table_2.pdf [63 KiB] HiDef png [112 KiB] Thumbnail [48 KiB] tex code % The yields extracted from the fit to the $B ^0_ s \rightarrow D ^{(*)+}_ s D ^{(*)-}_ s$ candidate sample. Table_3.pdf [52 KiB] HiDef png [108 KiB] Thumbnail [49 KiB] tex code % The yields extracted from the fit to the ${ B ^0 \rightarrow D^{(*)\pm}_{s} D_{}^{(*)\mp}}$ candidate sample. Table_4.pdf [52 KiB] HiDef png [107 KiB] Thumbnail [48 KiB] tex code % Systematic uncertainties, in % of the relevant branching fraction ratio, for the $B ^0_ s \rightarrow D ^{(*)+}_ s D ^{(*)-}_ s$ branching fraction ratios. Table_5.pdf [77 KiB] HiDef png [65 KiB] Thumbnail [31 KiB] tex code

Created on 23 August 2019.Citation count from INSPIRE on 23 August 2019.