B−→K−χc0 decay from charmed meson rescattering

We study the process B−→K−χc0 considering intermediate charmed meson rescattering effects. For this decay mode the naive factorization ansatz would predict a vanishing amplitude. We estimate contributions from the D(∗)sD(∗)→K−χc0 rescattering 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.