Observation of $B^{+}\to J\mathrm{/}\psi 3{\pi }^{+}2{\pi }^{-}$ and $B^{+}\to \psi (2S){\pi }^{+}{\pi }^{+}{\pi }^{-}$ decays

The decays $B^{+}\to J\mathrm{/}\psi 3{\pi }^{+}2{\pi }^{-}$ and $B^+\rightarrow \psi(2S) \pi^+\pi^+\pi^-$ are observed for the first time using a data sample corresponding to an integrated luminosity of $3.0f{b}^{-1}$, 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.