We consider hidden charm pentaquarks as hadroquarkonium states in a QCD inspired approach. Pentaquarks arise naturally as bound states of quarkonia excitations and ordinary baryons. The LHCb Pc(4450) pentaquark is interpreted as a ψ′-nucleon bound state with spin-parity J P =3/2. The partial decay width Γ(Pc(4450) → J / ψ + N) ≈ 11 MeV is calculated and turned out to be in agreement with the experimental data for Pc(4450). The Pc(4450) pentaquark is predicted to be a member of one of the two almost degenerate hidden-charm baryon octets with spin-parities J P = 1/2, 3/2. The masses and decay widths of the octet pentaquarks are calculated. The widths are small and comparable with the width of the Pc(4450) pentaquark, and the masses of the octet pentaquarks satisfy the Gell-Mann–Okubo relation. Interpretation of pentaquarks as loosely bound Σc and Σcdeuteronlike states is also considered. We determine quantum numbers of these bound states and calculate their masses in the one-pion exchange scenario. The hadroquarkonium and molecular approaches to exotic hadrons are compared and the relative advantages and drawbacks of each approach are discussed.

Document Type


Publication Date


Notes/Citation Information

Published in The European Physical Journal C, v. 78, issue 1, article 36, p. 1-15.

© The Author(s) 2018

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Digital Object Identifier (DOI)


Funding Information

This paper was supported by the NSF Grants PHY-1402593 and PHY-1724638. The work of M. V. P. is supported by CRC110 of DFG.

Funded by SCOAP3.