Measurement of the branching fractions for $B^+\to D^{+}D^-K^+$, $B^+\to D^{-}D^+K^+$, and $B^0\to D^{*-}D^0K^+$ decays

Information

LHCb-PAPER-2020-006
CERN-EP-2020-056
arXiv:2005.10264 [PDF]

(Submitted on 20 May 2020)
JHEP 12 (2020) 139
Inspire 1797220

Tools

Abstract

A measurement of four branching-fraction ratios for three-body decays of $B$ mesons involving two open-charm hadrons in the final state is presented. Run 1 and Run 2 $pp$ collision data are used, recorded by the LHCb experiment at centre-of-mass energies $7$, $8$, and $13$ TeV and corresponding to an integrated luminosity of $9$ fb$^{-1}$. The measured branching-fraction ratios are \[ \begin{eqnarray} \frac{\mathcal{B} (B^+\to D^{*+}D^-K^+)}{\mathcal{B} (B^+\to \overline{ D}{}^0 D^0 K^+)} &=& 0.517 \pm 0.015 \pm 0.013 \pm 0.011 , \\ \frac{\mathcal{B} (B^+\to D^{*-}D^+K^+)}{\mathcal{B} (B^+\to \overline{ D}{}^0 D^0 K^+)} &=& 0.577 \pm 0.016 \pm 0.013 \pm 0.013 , \\ \frac{\mathcal{B} (B^0\to D^{*-}D^0K^+)}{\mathcal{B} (B^0\to D^- D^0 K^+)} &=& 1.754 \pm 0.028 \pm 0.016 \pm 0.035 , \\ \frac{\mathcal{B} (B^+\to D^{*+}D^-K^+)}{\mathcal{B} (B^+\to D^{*-}D^+K^+)} &=& 0.907 \pm 0.033 \pm 0.014 ,\end{eqnarray} \] where the first of the uncertainties is statistical, the second systematic, and the third is due to the uncertainties on the $D$-meson branching fractions. These are the most accurate measurements of these ratios to date.

Figures and captions

Top left: internal $ W $ -emission diagram for the decays $ B ^+ \rightarrow D ^{-} D ^+ K ^+ $ and $ B ^+ \rightarrow D ^{+} D ^- K ^+ $ . Top right: external $ W $ -emission diagram for the decays $ B ^0 \rightarrow D ^{*-} D ^0 K ^+ $ and $ B ^0 \rightarrow D ^- D ^0 K ^+ $ . Bottom row: (left) external and (right) internal $ W $ -emission diagrams contributing to the $ B ^+ \rightarrow \overline{ D }{} {}^0 D ^0 K ^+ $ decay.	Fig1.pdf [2 MiB] HiDef png [59 KiB] Thumbnail [30 KiB] *.C file
Fits to the invariant-mass distributions $m( D ^{()} \overline{ D }{} K )$ of (left) $ B \rightarrow D ^ \overline{ D }{} K $ and (right) $ B \rightarrow D \overline{ D }{} K $ for the combined Run 1 and Run 2 samples. The stacked components are (red) combinatorial background and (blue) signal shape.	Fig2a.pdf [61 KiB] HiDef png [2 MiB] Thumbnail [1 MiB] *.C file
	Fig2b.pdf [42 KiB] HiDef png [1 MiB] Thumbnail [985 KiB] *.C file
Selection and reconstruction efficiency, $\varepsilon^{\mathrm{sel}}$, as a function of position in the two-body squared invariant-mass plane for the seven $ B \rightarrow D ^* \overline{ D }{} K $ modes, obtained using Run 1 simulated samples. A KDE smoothing has been applied. The blue lines indicate the kinematic boundaries and the numbers indicate the value of the efficiency at several points in the phase space.	Fig3.pdf [967 KiB] HiDef png [1 MiB] Thumbnail [739 KiB] *.C file
Selection and reconstruction efficiency, $\varepsilon^{\mathrm{sel}}$, as a function of position in the two-body squared invariant-mass plane for the seven $ B \rightarrow D ^* \overline{ D }{} K $ modes, obtained using Run 2 simulated samples. A KDE smoothing has been applied. The blue lines indicate the kinematic boundaries and the numbers indicate the values of the efficiency at several points in the phase space.	Fig4.pdf [968 KiB] HiDef png [1 MiB] Thumbnail [747 KiB] *.C file
Animated gif made out of all figures.	PAPER-2020-006.gif Thumbnail

Tables and captions

Decays under study. In the first column no assumption about the $ D $ final state is made. In the second column, however, the particular $ D $ decays are specified.	Table_1.pdf [66 KiB] HiDef png [139 KiB] Thumbnail [65 KiB] tex code
Table of all signal yields $N$ and efficiency and $ D $ -meson branching fraction corrected yields $ N^{\mathrm{corr}}$ with the residual peaking background subtracted. The values of corrected yields are rounded to the order of $10^6$. The uncertainties are statistical only.	Table_2.pdf [69 KiB] HiDef png [139 KiB] Thumbnail [68 KiB] tex code
Systematic uncertainties on $ N^{\mathrm{corr}}$ from the signal PDF parameters ($\sigma_{\mathrm{PDF}}$), the finite simulation samples ($\sigma_{\mathrm{MC}}$), the PID resampling ($\sigma_{\mathrm{PID}}$), the residual peaking background ($\sigma_{\mathrm{bkg}}$), and the total systematic uncertainty ($\sigma_{\mathrm{tot.}}$). All values are given as a percentage of the central value of $ N^{\mathrm{corr}}$ .	Table_3.pdf [71 KiB] HiDef png [101 KiB] Thumbnail [47 KiB] tex code

Supplementary Material [file]

Supplementary material full pdf	supple[..].pdf [256 KiB]
This ZIP file contains supplemetary material for the publication LHCb-PAPER-2020-006. The files are: supplementary.pdf : An overview of the extra figures .pdf, .png, .eps , .C: The figures in variuous formats	Fig1a-supp.pdf [21 KiB] HiDef png [406 KiB] Thumbnail [189 KiB] *C file
	Fig1b-supp.pdf [21 KiB] HiDef png [410 KiB] Thumbnail [186 KiB] *C file
	Fig1c-supp.pdf [21 KiB] HiDef png [408 KiB] Thumbnail [187 KiB] *C file
	Fig1d-supp.pdf [20 KiB] HiDef png [385 KiB] Thumbnail [177 KiB] *C file
	Fig1e-supp.pdf [21 KiB] HiDef png [405 KiB] Thumbnail [185 KiB] *C file
	Fig1f-supp.pdf [21 KiB] HiDef png [414 KiB] Thumbnail [189 KiB] *C file
	Fig1g-supp.pdf [21 KiB] HiDef png [400 KiB] Thumbnail [184 KiB] *C file
	Fig2a-supp.pdf [21 KiB] HiDef png [424 KiB] Thumbnail [194 KiB] *C file
	Fig2b-supp.pdf [21 KiB] HiDef png [435 KiB] Thumbnail [196 KiB] *C file
	Fig2c-supp.pdf [21 KiB] HiDef png [414 KiB] Thumbnail [189 KiB] *C file
	Fig2d-supp.pdf [21 KiB] HiDef png [419 KiB] Thumbnail [191 KiB] *C file