Kπ form factors, final state interactions and D+→K−π+π+ decays

We present a model for the decay D+→K−π+p+. The weak interaction part of this reaction is described using the effective weak Hamiltonian in the factorisation approach. Hadronic final state interactions are taken into account through the Kπ scalar and vector form factors fulfilling analyticity, unitarity and chiral symmetry constraints. Allowing for a global phase difference between the S and P waves of −65°, the Dalitz plot of the D+→K−π+π+ decay, the Kπ invariant mass spectra and the total branching ratio due to S‐wave interactions are well reproduced.