Dalitz plot analysis of the $D^+ \rightarrow K^- K^+ K^+$ decay with the isobar model

This note presents a study of the $K^-K^+$ S-wave amplitude in doubly Cabibbo-suppressed ${D^+ \rightarrow K^- K^+ K^+}$ decays performed using $2 \text{fb}^{-1}$ of data collected by the LHCb detector in $pp$ collisions at $8~\text{TeV}$ centre-of-mass energy. The Dalitz plot is studied under the assumption of the isobar model for resonance scattering. Models with combinations of resonant states are tested. Fits of comparable quality are obtained for different $K^-K^+$ S-wave parameterizations. The results obtained indicate that a variation of the S-wave phase at both ends of $K^-K^+$ spectrum is needed to describe the data. Further studies beyond the näive isobar model are foreseen to understand the $K^-K^+$ S-wave.