Study of B+c meson decays to charmonia plus multihadron final states

Four decay modes of the B+c meson into a J/ψ meson and multiple charged
kaons or pions are studied using proton-proton collision data, collected with the LHCb detector at centre-of-mass energies of 7, 8, and 13 TeV and corresponding to an integrated luminosity of 9 fb−1. The decay B+c →J/ψK+K−π+π+π− is observed for the first time, and evidence for the B+
c → J/ψ4π+3π− decay is found. The decay B+c → J/ψ3π+2π− is observed and the previous observation of the B+c → ψ(2S)π+π+π− decay is confirmed
using the ψ(2S) → J/ψπ+π− decay mode. Ratios of the branching fractions of these four B+c decay channels are measured.