cern.ch

Observation of $B_{c}^{+} \to J/\psi D^{(*)} K^{(*)}$ decays

[to restricted-access page]

Abstract

A search for the decays $B_c^+ \to J/\psi D^{(*)0} K^+$ and $B_c^+ \to J/\psi D^{(*)+} K^{*0}$ is performed with data collected at the LHCb experiment corresponding to an integrated luminosity of 3 fb$^{-1}$. The decays $B_c^+ \to J/\psi D^0 K^+$ and $B_c^+ \to J/\psi D^{*0} K^+$ are observed for the first time, while first evidence is reported for the $B_c^+ \to J/\psi D^{*+} K^{*0}$ and $B_c^+ \to J/\psi D^+ K^{*0}$ decays. The branching fractions of these decays are determined relative to the $B_c^+ \to J/\psi \pi^+$ decay. The $B_c^+$ mass is measured, using the $J/\psi D^0 K^+$ final state, to be $6274.28 \pm 1.40 (stat) \pm 0.32 (syst)$ MeV/$c^2$. This is the most precise single measurement of the $B_c^+$ mass to date.

Figures and captions

Diagrams for $ B _ c ^+ \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} D ^{(*)} K ^{(*)}$ decays mediated by $\overline b \rightarrow c \bar{c} \bar{s}$ and annihilation amplitudes.

Fig1a.pdf [110 KiB]
HiDef png [65 KiB]
Thumbnail [12 KiB]
*.C file
Fig1a.pdf
Fig1b.pdf [110 KiB]
HiDef png [71 KiB]
Thumbnail [14 KiB] *.C file
Fig1b.pdf
Fig1c.pdf [110 KiB]
HiDef png [87 KiB]
Thumbnail [16 KiB] *.C file
Fig1c.pdf

The invariant mass distribution of $ { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} D ^0 K ^+ $ candidates: (a) $ D ^0 \rightarrow K ^- \pi ^+ $ and $ D ^0 \rightarrow K ^- \pi ^+ \pi ^- \pi ^+ $ combined; (b) $ D ^0 \rightarrow K ^- \pi ^+ $ only, and the events are required to be TOS.

Fig2a.pdf [23 KiB]
HiDef png [470 KiB]
Thumbnail [98 KiB]
*.C file
Fig2a.pdf
Fig2b.pdf [22 KiB]
HiDef png [466 KiB]
Thumbnail [99 KiB] *.C file
Fig2b.pdf

The invariant mass distribution of (a,b) $ { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} D ^0 $, (c,d) $ D ^0 K ^+ $ and (e,f) $ { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} K ^+ $ combinations of background-subtracted (a,c,e) $ B _ c ^+ \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} D ^0 K ^+ $ and (b,d,f) $ B _ c ^+ \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} D ^{*0} K ^+ $ decays, where the $\gamma$ or $\pi ^0 $ in the $ D ^{*0} \rightarrow D ^0 \gamma/ D ^0 \pi ^0 $ decay is not reconstructed. Dashed lines show simulation assuming phase-space decay.

Fig3a.pdf [17 KiB]
HiDef png [314 KiB]
Thumbnail [74 KiB]
*.C file
Fig3a.pdf
Fig3b.pdf [17 KiB]
HiDef png [317 KiB]
Thumbnail [73 KiB] *.C file
Fig3b.pdf
Fig3c.pdf [18 KiB]
HiDef png [312 KiB]
Thumbnail [73 KiB] *.C file
Fig3c.pdf
Fig3d.pdf [18 KiB]
HiDef png [330 KiB]
Thumbnail [76 KiB] *.C file
Fig3d.pdf
Fig3e.pdf [18 KiB]
HiDef png [318 KiB]
Thumbnail [74 KiB] *.C file
Fig3e.pdf
Fig3f.pdf [18 KiB]
HiDef png [328 KiB]
Thumbnail [75 KiB] *.C file
Fig3f.pdf

The invariant mass distribution of (a,c) the $ B _ c ^+ \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} D ^{*+} K ^{*0} $ and (b,d) $ { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} D ^+ K ^{*0} $ candidates, (a,b) without and (c,d) with TOS requirements.

Fig4a.pdf [20 KiB]
HiDef png [374 KiB]
Thumbnail [82 KiB]
*.C file
Fig4a.pdf
Fig4b.pdf [18 KiB]
HiDef png [349 KiB]
Thumbnail [73 KiB] *.C file
Fig4b.pdf
Fig4c.pdf [20 KiB]
HiDef png [383 KiB]
Thumbnail [85 KiB] *.C file
Fig4c.pdf
Fig4d.pdf [18 KiB]
HiDef png [363 KiB]
Thumbnail [77 KiB] *.C file
Fig4d.pdf

The invariant mass distribution of the $ B _ c ^+ \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} \pi ^+ $ candidates.

Fig5.pdf [32 KiB]
HiDef png [446 KiB]
Thumbnail [87 KiB]
*.C file
Fig5.pdf

Animated gif made out of all figures.

PAPER-2016-055.gif
Thumbnail
thumbnail_PAPER-2016-055.gif

Tables and captions

Summary of systematic uncertainties on the ratios of the $ B _ c ^+ $ decay branching fractions, in %.

Table_1.pdf [61 KiB]
HiDef png [59 KiB]
Thumbnail [9 KiB]
tex code
Table_1.pdf

Summary of systematic uncertainties of the $ B _ c ^+$ mass measurement.

Table_2.pdf [31 KiB]
HiDef png [59 KiB]
Thumbnail [10 KiB]
tex code
Table_2.pdf

Supplementary Material [file]

Supplementary material full pdf

supple[..].pdf [108 KiB]
supplementary.pdf

This ZIP file contains supplemetary material for the publication LHCb-PAPER-2016-055. The files are: supplementary.pdf : An overview of the extra figures *.pdf, *.png, *.eps : The figures in variuous formats

Fig1.pdf [13 KiB]
HiDef png [330 KiB]
Thumbnail [67 KiB]
*C file
Fig1.pdf

Created on 18 December 2018.Citation count from INSPIRE on 18 December 2018.