Dalitz plot analyses of J/ψ → π~+ π~− π~0, J/ψ → K~+K~− π~0, and J/ψ → K~0_s K~±π~∓ produced via e~+e~− annihilation with initial-state radiation

摘要

We study the processes e~+e~− → γ_(ISR)J/ψ, where J/ψ → π~+π~−π~0, J/ψ → K~+K~−π~0, and J/ψ → K~0_S K~±π~∓ using a data sample of 519 fb~(−1) recorded with the BABAR detector operating at the SLAC PEP-Ⅱ asymmetric-energy e~+e~− collider at center-of-mass energies at and near the Υ(nS) (n = 2, 3, 4) resonances. We measure the ratio of branching fractions R_1= B(J/ψ→K~+K~−π~0)/B(J/ψ→π~+π~−π~0) and R_2= B(J/ψ→K~0_S K~±π~∓)/B(J/ψ→π~+π~−π~0). We perform Dalitz plot analyses of the three J/ψ decay modes and measure fractions for resonances contributing to the decays. We also analyze the J/ψ → π~+π~−π~0 decay using the Veneziano model. We observe structures compatible with the presence of ρ(1450) in all three J/ψ decay modes and measure the relative branching fraction: R(ρ(1450)) = B(ρ(1450)→K~+K~−)/B(ρ(1450)→π~+π~−) = 0.307 ± 0.084(stat) ± 0.082(sys).