Parametrizations of three-body hadronic B- and D-decay amplitudes

A short review of our recent work on amplitude parametrizations of three-body hadronic weak B and D decays is presented. The final states are here composed of three light mesons, namely the various charge πππ, Kππ and KKK¯$ \bar K $ states. These parametrizations are derived from previous calculations based on a quasi-two-body factorization approach where the two-body hadronic final state interactions are fully taken into account in terms of unitary S- and P-wave ππ, πK and KK¯$ \bar K $ form factors. They are an alternative to the isobar-model description and can be useful in the interpretation of CP asymmetries