K pi form factors, final state interactions and D+ arrow right K(-) pi (+) pi (+) decays

We present a model for the decay D+ arrow right K(-) pi (+) pi (+). 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 K pi 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 degree , the Dalitz plot of the D(+) arrow right K(-) pi (+) pi (+) decay, the K pi invariant mass spectra and the total branching ratio due to S-wave interactions are well reproduced.