# 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] HiDef png [357 KiB] Thumbnail [103 KiB] *.C file 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] HiDef png [244 KiB] Thumbnail [101 KiB] *.C file 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] HiDef png [248 KiB] Thumbnail [103 KiB] *.C file 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 [201 KiB] Thumbnail [85 KiB] *.C file Animated gif made out of all figures. PAPER-2011-044.gif Thumbnail

Created on 16 February 2019.Citation count from INSPIRE on 21 February 2019.