Invariant-mass spectrum of Formula Presented pair in the process Formula Presented

We show that the final-state interaction perfectly explains the recent experimental data of the BESIII Collaboration on the near-threshold invariant-mass spectrum of Formula Presented in the process Formula Presented. The position of the peak in the invariant-mass spectrum is above the threshold, though the interaction of Formula Presented and Formula Presented is due to an attractive potential. This potential has a simple form and depends only on two parameters. We show that the invariant-mass spectrum is consistent with the quantum numbers Formula Presented and Formula Presented of Formula Presented pair but the quantum numbers Formula Presented are less likely.