Pc(4457)+, Pc(4440)+, and Pc(4312)+: Molecules or compact pentaquarks?

In a chromomagnetic model, we analyze the properties of the newly observed Pc(4457)+, Pc(4440)+, and Pc(4312)+ states. We estimate the masses of the (uud)8c(cc¯)8c and (uds)8c(cc¯)8c pentaquark states by considering the isospin breaking effects. Their values are determined by calculating mass distances from the Σc++D− and Ξc′+D− thresholds, respectively. It is found that the isospin breaking effects on the spectrum are small. From the uncertainty consideration and the rearrangement decay properties in a simple model, we find that it is possible to assign the Pc(4457)+, Pc(4440)+, and Pc(4312)+ as JP=3/2−, 1/2−, and 3/2− pentaquark states, respectively. The assignment in the molecule picture can be different, in particular for the Pc(4312)+. The information from open-charm channels, e.g., B[Pc→Σc++D−]/B[Pc→J/ψp], will play an important role in distinguishing the inner structures of the Pc states. Discussions and predictions based on the calculations are also given.