Study of Bc+ 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.