Understanding the nature of heavy pentaquarks and searching for them in pion-induced reactions

We investigate the reaction π−p→π−J/ψpπ−p→π−J/ψp via the open-charm hadron rescattering diagrams. Due to the presence of the triangle singularity (TS) in the rescattering amplitudes, the TS peaks can simulate the pentaquark-like resonances arising in the J/ψpJ/ψp invariant mass distributions, which may bring ambiguities on our understanding of the nature of the exotic states. Searching for the heavy pentaquark in different processes may help us to clarify the ambiguities, because of the highly process-dependent characteristic of the TS mechanism.