Multimeson model for the D + → K + K − K + decay amplitude

We propose an approach to describe the D+→K−K+K+ decay amplitude, based on chiral effective Lagrangians, which can be used to extract information about KK¯ scattering. It relies on factorization and its main novel feature is the role played by multimeson interactions characteristic of chiral symmetry. Our trial function is an alternative to the widely used isobar model and includes both nonresonant three-body interactions and two-body rescattering amplitudes, based on coupled channels and resonances, for S- and P-waves with isospin 0 and 1. The latter are unitarized in the K-matrix approximation and represent the only source of complex phases in the problem. The nonresonant component, given by chiral symmetry as a real polynomium, is an important prediction of the model, which goes beyond the (2+1) approximation. Our approach allows one to disentangle the two-body scalar contributions with different isospins, associated with the f0(980) and a0(980) channels. We show how the KK¯ amplitude can be obtained from the decay D+→K−K+K+ and discuss extensions to other three-body final states.