Abstract
The recent observation of two hidden-charm pentaquark states by LHCb collaborations prompted us to investigate the exotic states close to the , , , , and thresholds. We therefore studied the hadronic molecules that form the coupled-channel system of and . As the heavy quark spin symmetry manifests the mass degenerations of and mesons, and of and baryons, the coupled channels of are important in these molecules. In addition, we consider the coupling to the channel whose thresholds are near the thresholds, and the coupling to the state with nonzero orbital angular momentum mixed by the tensor force. This full coupled-channel analysis of with larger orbital angular momentum has never been performed before. By solving the coupled-channel Schrödinger equations with the one meson exchange potentials with respect to the heavy quark spin and chiral symmetries, we studied the hidden-charm hadronic molecules with and . We conclude that the assignment of the observed pentaquarks is for and for , which is in agreement with the results of the LHCb analysis. In addition, we give predictions for other states at 4136.0, 4307.9 and 4348.7 MeV in , and 4206.7 MeV in , which can be further investigated by means of experiment.
- Received 11 November 2016
DOI:https://doi.org/10.1103/PhysRevD.96.014018
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