The baryo-quarkonium picture for hidden-charm and bottom pentaquarks and LHCb Pc(4380) and Pc(4450) states

We study baryo-charmonium [eta(c)- and J/psi-N*, eta(c)(2S)-, psi(2S)- and chi(c)(1P)-N] and baryo-bottomonium [eta(b)(2S)-, Upsilon(28)- and chi(b)(1P)-N] bound states, where N is the nucleon and N* a nucleon resonance. In the baryo-quarkonium model, the five qqqQ (Q) over bar quarks are arranged in terms of a heavy quarkonium core, Q (Q) over bar, embedded in light baryonic matter, qqq, with q = u or d. The interaction between the Q (Q) over bar core and the light baryon can be written in terms of the QCD multipole expansion. The spectrum of baryo-charmonium states is calculated and the results compared with the existing experimental data. In particular, we can interpret the recently discovered P-c(4380) and P-c(4450) pentaquarks as psi*(2S)-N and chi(c2)(1P)-N bound states, respectively. We observe that in the baryo-bottomonium sector the binding energies are, on average, slightly larger than those of baryo-charmonia. Because of this, the hidden bottom pentaquarks are more likely to form than their hidden-charm counterparts. We thus suggest the experimentalists to look for five-quark states in the hidden-bottom sector in the 10.4-10.9 GeV energy region. (C) 2018 The Authors. Published by Elsevier B.V.