Nonleptonic B to charmonium decays generally show deviations from the factorization predictions. For example, the mode B Ϫ →K Ϫ c0 has been experimentally observed with a sizable branching fraction while its factorized amplitude vanishes. We investigate the role of rescattering effects mediated by intermediate charmed meson production in this class of decay modes, and consider B Ϫ →K Ϫ h c with h c the J PC ϭ1 ϩϪ c c meson. Using an effective Lagrangian describing interactions of pairs of heavy-light Qq mesons with a quarkonium state, we relate this mode to the analogous mode with c0 in the final state. We find B(B Ϫ →K Ϫ h c ) large enough to be measured at B factories, so that this decay mode could be used to study the poorly known h c .

We study the process B − → K − χ c0 considering intermediate charmed meson rescattering effects. For this decay mode the naive factorization ansatz would predict a vanishing amplitude. We estimate contributions from the Drescattering amplitudes, and compare the result with recent experimental measurements. We find that rescattering effects are able to produce a large branching ratio consistent with measurements by Belle Collaboration. We also consider rescattering effects in B − → K − J/ψ, arguing that they play a similar role in producing a large branching fraction for this colour-suppressed decay mode.