We revisit the hidden-charm pentaquark states Pc(4380) and Pc(4450) using the method of QCD sum rules by requiring the pole contribution to be larger than or around 30% to better insure the one-pole parametrization to be valid. We find two mixing currents and our results suggest that the Pc(4380) and Pc(4450) can be identified as hidden-charm pentaquark states having J P = 3/2 − and 5/2 + , respectively, while there still exist other possible spin-parity assignments, such as J P = 3/2 + and J P = 5/2 − , which needs to be clarified in further theoretical and experimental studies.All the local hidden-charm pentaquark interpolating currents have been systematically constructed in Refs. [57,58], and some of them were selected to perform QCD sum rule analyses. The results suggest that the P c (4380) and P c (4450) can be interpreted as hidden-charm pentaquark states composed of anticharmed mesons and charmed baryons. However, the analyses therein use one criterion which is not optimized, that is to require the pole contribution to be larger than 10% to insure the one-pole parametrization to be valid. This value is not so significant, and accordingly, the question arises whether we can find a larger pole contribution to better insure the one-pole parametrization?In the present study we try to answer this question in order to find better (more reliable) QCD sum rule results. Especially, we find the following two mixing currents: * ] channels, etc.

We use the method of QCD sum rules to systematically study the mass spectrum of hidden-charm pentaquarks of spin J = 1 2 / 3 2 / 5 2 and with the quark content uudcc. Our results suggest that the P c (4380) and P c (4450) can be identified as hidden-charm pentaquark states having J P = 3/2 − and 5/2 + , respectively.