LHCb pentaquarks as a baryon-Ψ(2S) bound state: Prediction of isospin-3/2 pentaquarks with hidden charm

The pentaquark P-c(+)(4450) recently discovered by the LHCb has been interpreted as a bound state of Psi(2S) and a nucleon. The charmonium-nucleon interaction which provides the binding mechanism is given, in the heavy-quark limit, in terms of charmonium chromoelectric polarizabilities and densities of the nucleon energy-momentum tensor. In this work, we show in a model-independent way, by exploring general properties of the effective interaction, that Psi(2S) can form bound states with a nucleon and Delta. Using the Skyrme model to evaluate the effective interaction in the large-N-c limit and estimate 1/N-c corrections, we confirm the results from prior work which were based on a different effective model (chiral quark soliton model). This shows that the interpretation of P-c(+)(4450) is remarkably robust and weakly dependent on the details of the effective theories for the nucleon energy-momentum tensor. We explore the formalism further and present robust predictions of isospin-3/2 bound states of Psi(2S) and Delta with masses around 4.5 GeV and widths around 70 MeV. The approach also predicts broader resonances in the Psi(2S)-Delta channel at 4.9 GeV with widths of the order of 150 MeV. We discuss in which reactions these new isospin-3/2 pentaquarks with hidden charm can be observed.