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First observation of decay $B_c^+\to J/\psi \pi^+\pi^-\pi^+$

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Abstract

The decay Bc+ --> J/psi pi+pi-pi+ is observed for the first time, using 0.8 fb-1 of pp collisions at sqrt{s}=7 TeV collected by the LHCb experiment. The ratio of branching fractions BR(Bc+ --> J/psi pi+pi-pi+)/BR(B_c+ --> J/psi pi+) is measured to be 2.41+-0.30+-0.33, where the first uncertainty is statistical and the second systematic. The result is in agreement with theoretical predictions.

Figures and captions

Invariant mass distribution of $B_c^+\rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} \pi^+\pi^-\pi^+$ (top) and $B_c^+\rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} \pi^+$ (bottom) candidates. The maximum likelihood fits of $B_c^+$ signals are superimposed.

fig3p_[..].pdf [18 KiB]
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fig3p_bcfits.pdf

Invariant mass distribution of the $\pi^+\pi^-\pi^+$ combinations for the sideband-subtracted $B_c^+\rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} \pi^+\pi^-\pi^+$ data (points) and signal simulation (lines). The solid blue line corresponds to the BLL simulations, the PH model is shown as a green dashed line and the PHPOL model is shown as a red dotted line. All error bars are statistical.

fig3p_ppp.pdf [15 KiB]
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fig3p_ppp.pdf

Invariant mass distribution of the $\pi^+\pi^-$ combinations (two entries per $B_c^+$ candidate) for the sideband-subtracted $B_c^+\rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} \pi^+\pi^-\pi^+$ data (points) and signal simulation (lines). The solid blue line corresponds to the BLL simulations, the PH model is shown as a green dashed line and the PHPOL model is shown as a red dotted line. All error bars are statistical.

fig3p_pp.pdf [16 KiB]
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*.C file
fig3p_pp.pdf

Distributions of the cosine of the angle between the $\mu^+$ and $B_c^+$ boosted to the rest frame of the $ { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} $ meson for the sideband-subtracted $B_c^+\rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} \pi^+$ (top) and $B_c^+\rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} \pi^+\pi^-\pi^+$ (bottom) data (points) and signal simulation (lines). In the bottom plot, the solid blue line corresponds to the BLL simulations, the PH model is shown as a green dashed line and the PHPOL model is shown as a red dotted line. All error bars are statistical.

fig3p_[..].pdf [16 KiB]
HiDef png [192 KiB]
Thumbnail [82 KiB]
*.C file
fig3p_muhel.pdf

Animated gif made out of all figures.

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