# Observation of $B^+\rightarrow J/\psi 3\pi^+ 2\pi^-$ and $B^+\rightarrow \psi(2S) \pi^+\pi^+\pi^-$ decays

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## Abstract

The decays $B^+\rightarrow J/\psi 3\pi^+ 2\pi^-$ and $B^+\rightarrow \psi(2S) \pi^+\pi^+\pi^-$ are observed for the first time using a data sample corresponding to an integrated luminosity of $3.0fb^{-1}$, collected by the LHCb experiment in proton-proton collisions at the centre-of-mass energies of 7 and 8 TeV. The branching fractions relative to that of $B^+ \rightarrow \psi(2S)K^+$ are measured to be \begin{eqnarray*} \frac {\mathcal{B}\left(B^+\rightarrow J/\psi 3\pi^+ 2\pi^- \right)} {\mathcal{B}\left(B^+ \rightarrow \psi(2S)K^+ \right)} & = & \left(1.88\pm0.17\pm0.09\right)\times10^{-2}, \frac {\mathcal{B}\left(B^+\rightarrow \psi(2S) \pi^+\pi^+\pi^- \right)} {\mathcal{B}\left(B^+ \rightarrow \psi(2S)K^+ \right)} & = & \left(3.04\pm0.50\pm0.26\right)\times10^{-2}, \end{eqnarray*} where the first uncertainties are statistical and the second are systematic.

## Figures and captions

 (a) Mass distributions of the selected $B ^+ \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} 3\pi ^+ 2\pi ^-$ candidates. (b) Sum of mass distributions for all backgrounddash-subtracted ${ J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} \pi ^+ \pi ^-$ combinations. The total fit function is shown with thick solid (orange) lines and the signal contribution with thin solid (red) lines. The dashed (blue) lines represent the combinatorial background and nondash-resonance component for plots (a) and (b), respectively. Fig_1.pdf [75 KiB] HiDef png [210 KiB] Thumbnail [187 KiB] *.C file tex code Mass distributions (a) of the selected $B ^+ \rightarrow \psi {(2\mathrm{S})} K ^+$ candidates and (b) backgrounddash-subtracted ${ J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} \pi ^+ \pi ^-$ combination. The total fit function is shown with thick solid (orange) lines and the signal contribution with thin solid (red) lines. The dashed (blue) lines represent the combinatorial background and nondash-resonance component for plots (a) and (b), respectively. Fig_2.pdf [76 KiB] HiDef png [197 KiB] Thumbnail [156 KiB] *.C file tex code (a) Mass distribution of the selected $B ^+ \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} 3\pi ^+ 2\pi ^-$ candidates with the additional requirement of every ${ J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} \pi ^+ \pi ^-$ combination to be outside of $\pm6 {\mathrm{ Me V /}c^2}$ around the known $\psi {(2\mathrm{S})}$ mass. The total fit function, the $B ^+$ signal contribution and the combinatorial background are shown with thick solid (orange), thin solid (red) and dashed (blue) lines, respectively. (b) Sum of mass distributions for all possible backgrounddash-subtracted $\pi ^+ \pi ^-$ combinations. The factorisationdash-based model prediction is shown by a solid (red) line, and the expectation from the phasedash-space model is shown by a dashed (blue) line. The total fit function, shown with a dotted (green) line, is an incoherent sum of a relativistic Breitdash-Wigner function with the mean and natural width fixed to the known $\rho ^{0}$ values and a phasedash-space function multiplied by a seconddash-order polynomial. Fig_3.pdf [77 KiB] HiDef png [227 KiB] Thumbnail [203 KiB] *.C file tex code Distributions of (a) $\pi ^- \pi ^-$, (b) $\pi ^+ \pi ^+$, (c) $\pi ^+ \pi ^+ \pi ^-$, (d) $\pi ^+ \pi ^- \pi ^-$, (e) $\pi ^+ \pi ^+ \pi ^+$, (f) $2\pi ^+ 2\pi ^-$, (g) $3\pi ^+ \pi ^-$ and (h) $3\pi ^+ 2\pi ^-$ masses in the $B ^+ \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} 3\pi ^+ 2\pi ^-$ decay. The prediction from the factorisationdash-based model is shown by solid (red) lines, and the expectation from the phasedash-space model is shown by dashed (blue) lines. Fig_4.pdf [166 KiB] HiDef png [550 KiB] Thumbnail [511 KiB] *.C file tex code Distributions of (a) $\pi ^+ \pi ^-$, (b) $\pi ^+ \pi ^+$ and (c) $\pi ^+ \pi ^+ \pi ^-$ masses in the $B ^+ \rightarrow \psi {(2\mathrm{S})} \pi ^+ \pi ^+ \pi ^-$ decay. The predictions from the factorisationdash-based model is shown by solid (red) lines, and the expectation from the phasedash-space model is shown by dashed (blue) lines. Fig_5.pdf [90 KiB] HiDef png [246 KiB] Thumbnail [223 KiB] *.C file tex code Animated gif made out of all figures. PAPER-2016-040.gif Thumbnail

## Tables and captions

 Signal yields, $N$, of $B ^+$ decay channels. Uncertainties are statistical only. Table_1.pdf [43 KiB] HiDef png [51 KiB] Thumbnail [24 KiB] tex code The $\chi^2$ per degree of freedom for the factorisationdash-based and phasedash-space models for the multipion system in nondash-resonant $B ^+ \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} 3\pi ^+ 2\pi ^-$ decays. Table_2.pdf [36 KiB] HiDef png [53 KiB] Thumbnail [28 KiB] tex code The $\chi^2$ per degree of freedom for the factorisationdash-based and phasedash-space models for the multipion system recoiling against $\psi {(2\mathrm{S})}$ in $B ^+ \rightarrow \psi {(2\mathrm{S})} \pi ^+ \pi ^+ \pi ^-$ decays. Table_3.pdf [36 KiB] HiDef png [28 KiB] Thumbnail [14 KiB] tex code Relative systematic uncertainties (in %) for the ratios of branching fractions. The total uncertainty is the quadratic sum of the individual components. Table_4.pdf [55 KiB] HiDef png [65 KiB] Thumbnail [31 KiB] tex code

Created on 18 January 2020.