Abstract
The LHCb Collaboration announced two pentaquark-like structures in the invariant mass distribution. We show that the current information on the narrow structure at 4.45 GeV is compatible with kinematical effects of the rescattering from to : First, it is located exactly at the threshold. Second, the mass of the four-star well-established is such that a leading Landau singularity from a triangle diagram can coincidentally appear at the threshold, and third, there is a narrow structure at the threshold but not at the and thresholds. In order to check whether that structure corresponds to a real exotic resonance, one can measure the process . If the structure exists in the invariant mass distribution as well, then the structure cannot be just a kinematical effect but is a real resonance; otherwise, one cannot conclude that is another exotic hadron. In addition, it is also worthwhile to measure the decay : a narrow structure at 4.45 GeV but not at the and thresholds would exclude the possibility of a pure kinematical effect.
- Received 20 July 2015
DOI:https://doi.org/10.1103/PhysRevD.92.071502
© 2015 American Physical Society