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.

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.

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.

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.

Animated gif made out of all figures.