Dalitz plot analysis of the D⁺ → K⁻K⁺K⁺ decay

The resonant structure of the doubly Cabibbo-suppressed decay D⁺ → K⁻K⁺K⁺ is studied for the first time. The measurement is based on a sample of pp-collision data, collected at a centre-of-mass energy of 8 TeV with the LHCb detector and corresponding to an integrated luminosity of 2 fb⁻¹. The amplitude analysis of this decay is performed with the isobar model and a phenomenological model based on an effective chiral Lagrangian. In both models the S-wave component in the K⁻K⁺ system is dominant, with a small contribution of the φ(1020) meson and a negligible contribution from tensor resonances. The K⁺K⁻ scattering amplitudes for the considered combinations of spin (0,1) and isospin (0,1) of the two-body system are obtained from the Dalitz plot fit with the phenomenological decay amplitude.