The hidden charm pentaquarks are the hidden color-octet uud baryons?

The I(JP)=12(12−), 12(32−), and 12(52−)uudcc‾ pentaquarks are investigated by the quark cluster model. This model, which reproduces the mass spectra of the color-singlet S-wave q3 baryons and qq‾ mesons, also enables us to evaluate the quark interaction in the color-octet uud configurations. It is shown that the color-octet isospin-12 spin-32uud configuration gains an attraction. The uudcc‾ states with this configuration have structures around the Σc(⁎)D‾(⁎) thresholds: one bound state, two resonances, and one large cusp are found. We argue that the negative parity pentaquark found by the LHCb experiments may be given by these structures.