Charm rescattering in B 0 → K 0 ℓ ¯ ℓ : an improved analysis

We improve upon previous explicit estimates of charm rescattering contributions to the decay $B^0\to K^0\overline{\ell }\ell$ by including contributions from dipole interactions with the intermediate charm-meson states, and by further investigating the structure of the electromagnetic form factors. Using a model of fundamental meson fields inspired by heavy-hadron chiral perturbation theory, augmented by form factors motivated by theoretical considerations as well as experimental data, we provide a thorough investigation of rescattering contributions induced by intermediate $D_{}^{(\ast )}D_s^{(\ast )}$ states.