Scalar resonances in the D+ → K−K+K+ decay

Abstract

We study theoretically the resonant structure of the double Cabibbo suppressed 𝐷+ →𝐾−⁢𝐾+⁢𝐾+ decay. We start from an elementary production diagram, considered subleading in previous approaches, which cannot produce a final 𝐾−⁢𝐾+ pair at the tree level but which we show to be able to provide the strength of the decay through final meson-meson state interaction. The different meson-meson elementary productions are related through SU(3), and the final rescattering is implemented from a suitable implementation of unitary extensions of chiral perturbation theory, which generate dynamically the scalar resonances 𝑓0⁡(980) and 𝑎0⁡(980). We obtain a good agreement with recent experimental data from the LHCb Collaboration with a minimal freedom in the fit and show the dominance of the 𝑎0⁡(980) contribution close to the threshold of the 𝐾−⁢𝐾+ spectrum.