- Open Access
Analytic electromagnetic signatures of compact pentaquark structure: A multicurrent QCD light-cone sum rules analysis of the states
Phys. Rev. D 114, 014050 – Published 23 July, 2026
DOI: https://doi.org/10.1103/8p4m-zbpb
Abstract
Probing the internal organization of hidden-charm pentaquarks—including the spin-color correlations that distinguish compact diquark-diquark-antiquark configurations from loosely bound hadronic molecules—requires observables that go beyond mass spectroscopy. We argue that multicurrent QCD light-cone sum rules provide a diagnostic framework for this problem, not only through the expected sensitivity of the magnetic moment to the internal spin structure but, more importantly, through exact analytic relations among the flavor-sector contributions that are enforced by the algebra of the interpolating currents themselves. We identify two such signatures that emerge from our analysis of compact diquark-diquark-antiquark configurations: (i) for any of the four currents considered the light-quark contributions satisfy the exact ratio , reflecting a common Lorentz-color kernel that couples and only through their electric charges; and (ii) for the current the charm-quark contribution vanishes identically, , arising not from the pseudoscalar embedding of the charm diquark alone—since the same embedding occurs in , which yields a nonzero —but from the specific Dirac structure associated with the anticharm coupling in the global current, which produces an analytic cancellation in the operator product expansion. We illustrate these signatures through explicit calculations using four independent diquark-diquark-antiquark interpolating currents , assumed to carry , and obtain , , , and . These four predictions are then assigned to the observed and resonances on the basis of the mass predictions of recent QCD sum rule analyses; we emphasize, however, that the corresponding mass uncertainties accommodate either state within of all four currents, so this current-to-state mapping is adopted only as an auxiliary phenomenological choice. The predicted magnitudes lie systematically above quark-model and heavy pentaquark chiral perturbation theory expectations (). Applying the same flavor-decomposition procedure to two previous molecular LCSR analyses of the same states yields rather than , providing an LCSR-internal contrast that operates at the flavor-decomposed level even when total magnitudes are comparable. Crucially, the two analytic signatures identified here are immune to the ambiguity of the state-to-current pairing and therefore offer falsifiable tests of the compact picture that survive the unavoidable phenomenological assumptions of mass-based assignments.
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References (74)
- M. Gell-Mann, A schematic model of baryons and mesons, Phys. Lett. 8, 214 (1964).
- S. K. Choi et al., Observation of a narrow charmonium-like state in exclusive decays, Phys. Rev. Lett. 91, 262001 (2003).
- R. Aaij et al., Observation of resonances consistent with pentaquark states in decays, Phys. Rev. Lett. 115, 072001 (2015).
- R. Aaij et al., Observation of a narrow pentaquark state, , and of two-peak structure of the , Phys. Rev. Lett. 122, 222001 (2019).
- R. Aaij et al., Evidence of a structure and observation of excited states in the decay, Sci. Bull. 66, 1278 (2021).
- I. Adachi et al., Search for Pcs(4459) and Pcs(4338) in Upsilon(1S,2S) inclusive decays at Belle, Phys. Rev. Lett. 135, 041901 (2025).
- R. Aaij et al., Evidence for a new structure in the and systems in decays, Phys. Rev. Lett. 128, 062001 (2022).
- R. Aaij et al., Observation of a resonance consistent with a strange pentaquark candidate in decays, Phys. Rev. Lett. 131, 031901 (2023).
- M.-Z. Liu, Y.-W. Pan, Z.-W. Liu, T.-W. Wu, J.-X. Lu, and L.-S. Geng, Three ways to decipher the nature of exotic hadrons: Multiplets, three-body hadronic molecules, and correlation functions, Phys. Rep. 1108, 1 (2025).
- L. Meng, B. Wang, G.-J. Wang, and S.-L. Zhu, Chiral perturbation theory for heavy hadrons and chiral effective field theory for heavy hadronic molecules, Phys. Rep. 1019, 1 (2023).
- H.-X. Chen, W. Chen, X. Liu, Y.-R. Liu, and S.-L. Zhu, An updated review of the new hadron states, Rep. Prog. Phys. 86, 026201 (2023).
- A. Esposito, A. L. Guerrieri, F. Piccinini, A. Pilloni, and A. D. Polosa, Four-quark hadrons: An updated review, Int. J. Mod. Phys. A 30, 1530002 (2015).
- A. Esposito, A. Pilloni, and A. D. Polosa, Multiquark resonances, Phys. Rep. 668, 1 (2017).
- S. L. Olsen, T. Skwarnicki, and D. Zieminska, Nonstandard heavy mesons and baryons: Experimental evidence, Rev. Mod. Phys. 90, 015003 (2018).
- R. F. Lebed, R. E. Mitchell, and E. S. Swanson, Heavy-quark QCD exotica, Prog. Part. Nucl. Phys. 93, 143 (2017).
- M. Nielsen, F. S. Navarra, and S. H. Lee, New charmonium states in QCD sum rules: A concise review, Phys. Rep. 497, 41 (2010).
- N. Brambilla, S. Eidelman, C. Hanhart, A. Nefediev, C.-P. Shen, C. E. Thomas, A. Vairo, and C.-Z. Yuan, The states: Experimental and theoretical status and perspectives, Phys. Rep. 873, 1 (2020).
- S. Agaev, K. Azizi, and H. Sundu, Four-quark exotic mesons, Turk. J. Phys. 44, 95 (2020).
- H.-X. Chen, W. Chen, X. Liu, and S.-L. Zhu, The hidden-charm pentaquark and tetraquark states, Phys. Rep. 639, 1 (2016).
- A. Ali, J. S. Lange, and S. Stone, Exotics: Heavy pentaquarks and tetraquarks, Prog. Part. Nucl. Phys. 97, 123 (2017).
- F.-K. Guo, C. Hanhart, U.-G. Meißner, Q. Wang, Q. Zhao, and B.-S. Zou, Hadronic molecules, Rev. Mod. Phys. 90, 015004 (2018); 94, 029901(E) (2022).
- Y.-R. Liu, H.-X. Chen, W. Chen, X. Liu, and S.-L. Zhu, Pentaquark and tetraquark states, Prog. Part. Nucl. Phys. 107, 237 (2019).
- G. Yang, J. Ping, and J. Segovia, Tetra- and penta-quark structures in the constituent quark model, Symmetry 12, 1869 (2020).
- X.-K. Dong, F.-K. Guo, and B.-S. Zou, A survey of heavy-antiheavy hadronic molecules, Prog. Phys. 41, 65 (2021).
- X.-K. Dong, F.-K. Guo, and B.-S. Zou, A survey of heavy–heavy hadronic molecules, Commun. Theor. Phys. 73, 125201 (2021).
- U. Özdem, Electromagnetic tomography of spin- hidden-charm strange pentaquarks, J. High Energy Phys. 02 (2026) 207.
- U. Özdem, Shedding light on the nature of the Pcs(4459) pentaquark state, Phys. Rev. D 111, 074038 (2025).
- U. Özdem, Elucidating the nature of hidden-charm pentaquark states with spin-32 through their electromagnetic form factors, Phys. Lett. B 851, 138551 (2024).
- U. Özdem, Electromagnetic properties of (*)’, (*), (*) and (*) pentaquarks, Phys. Lett. B 846, 138267 (2023).
- U. Özdem, Investigation of magnetic moment of Pcs(4338) and Pcs(4459) pentaquark states, Phys. Lett. B 836, 137635 (2023).
- G.-J. Wang, R. Chen, L. Ma, X. Liu, and S.-L. Zhu, Magnetic moments of the hidden-charm pentaquark states, Phys. Rev. D 94, 094018 (2016).
- E. Ortiz-Pacheco, R. Bijker, and C. Fernández-Ramírez, Hidden charm pentaquarks: mass spectrum, magnetic moments, and photocouplings, J. Phys. G 46, 065104 (2019).
- Y.-J. Xu, Y.-L. Liu, and M.-Q. Huang, The magnetic moment of as a molecular state, Eur. Phys. J. C 81, 421 (2021).
- U. Özdem and K. Azizi, Electromagnetic multipole moments of the pentaquark in light-cone QCD, Eur. Phys. J. C 78, 379 (2018).
- U. Özdem, Magnetic dipole moments of the hidden-charm pentaquark states: , and , Eur. Phys. J. C 81, 277 (2021).
- M.-W. Li, Z.-W. Liu, Z.-F. Sun, and R. Chen, Magnetic moments and transition magnetic moments of Pc and Pcs states, Phys. Rev. D 104, 054016 (2021).
- F. Gao and H.-S. Li, Magnetic moments of hidden-charm strange pentaquark states*, Chin. Phys. C 46, 123111 (2022).
- F. Guo and H.-S. Li, Analysis of the hidden-charm pentaquark states based on magnetic moment and transition magnetic moment, Eur. Phys. J. C 84, 392 (2024).
- F.-L. Wang, S.-Q. Luo, H.-Y. Zhou, Z.-W. Liu, and X. Liu, Exploring the electromagnetic properties of the (’,*)* and (*)* molecular states, Phys. Rev. D 108, 034006 (2023).
- F.-L. Wang, H.-Y. Zhou, Z.-W. Liu, and X. Liu, What can we learn from the electromagnetic properties of hidden-charm molecular pentaquarks with single strangeness?, Phys. Rev. D 106, 054020 (2022).
- U. Özdem, Analysis of the isospin Eigenstate , , and pentaquarks by their electromagnetic properties, Eur. Phys. J. C 84, 769 (2024).
- H.-S. Li, F. Guo, Y.-D. Lei, and F. Gao, Magnetic moments and axial charges of the octet hidden-charm molecular pentaquark family, Phys. Rev. D 109, 094027 (2024).
- H.-S. Li, Molecular pentaquark magnetic moments in heavy pentaquark chiral perturbation theory, Phys. Rev. D 109, 114039 (2024).
- H. Mutuk and X.-W. Kang, Unveiling the structure of hidden-bottom strange pentaquarks via magnetic moments, Phys. Lett. B 855, 138772 (2024).
- H. Mutuk, Magnetic moments of hidden-bottom pentaquark states, Eur. Phys. J. C 84, 874 (2024).
- H. Mutuk, Magnetic moments of hidden-charm pentaquarks in the diquark–diquark–antiquark scheme, Chin. J. Phys. (Taipei) 97, 1406 (2025).
- U. Özdem, Insight into the nature of the and related pentaquarks, Eur. Phys. J. C 85, 624 (2025).
- U. Özdem, Probing the electromagnetic structure of the pentaquark: Insights from a diquark–diquark–antiquark picture for and states, Eur. Phys. J. C 85, 704 (2025).
- S.-H. Zhu, F.-L. Wang, and X. Liu, Electromagnetic characteristics as probes into the inner structures of the predicted molecular states, Eur. Phys. J. C 86, 385 (2026).
- U. Özdem, Hidden-charm pentaquarks: Electromagnetic structure in a diquark–diquark–antiquark model, Eur. Phys. J. C 86, 359 (2026).
- U. Özdem, Electromagnetic form factors: A window into the , , and molecular structure, Eur. Phys. J. C 86, 675 (2026).
- H. Mutuk and X.-W. Kang, Magnetic moments of open bottom–charm molecular pentaquark octets, arXiv:2603.27657.
- V. L. Chernyak and I. R. Zhitnitsky, B meson exclusive decays into baryons, Nucl. Phys. B345, 137 (1990).
- V. M. Braun and I. E. Filyanov, QCD sum rules in exclusive kinematics and pion wave function, Z. Phys. C 44, 157 (1989).
- I. I. Balitsky, V. M. Braun, and A. V. Kolesnichenko, Radiative decay sigma+— p gamma in quantum chromodynamics, Nucl. Phys. B312, 509 (1989).
- P. Ball, V. M. Braun, and N. Kivel, Photon distribution amplitudes in QCD, Nucl. Phys. B649, 263 (2003).
- V. A. Novikov, M. A. Shifman, A. I. Vainshtein, and V. I. Zakharov, Calculations in external fields in quantum chromodynamics. Technical review, Fortschr. Phys. 32, 585 (1984).
- B. L. Ioffe and A. V. Smilga, Nucleon magnetic moments and magnetic properties of vacuum in QCD, Nucl. Phys. B232, 109 (1984).
- D. B. Leinweber, R. M. Woloshyn, and T. Draper, Electromagnetic structure of octet baryons, Phys. Rev. D 43, 1659 (1991).
- Z.-G. Wang, Analysis of the scalar and axial-vector heavy diquark states with QCD sum rules, Eur. Phys. J. C 71, 1524 (2011).
- R. T. Kleiv, T. G. Steele, A. Zhang, and I. Blokland, Heavy-light diquark masses from QCD sum rules and constituent diquark models of tetraquarks, Phys. Rev. D 87, 125018 (2013).
- Z.-G. Wang and Q. Xin, Analysis of the hidden-charm pentaquark candidates in the mass spectrum via the QCD sum rules, Eur. Phys. J. C 86, 472 (2026).
- I. I. Balitsky and V. M. Braun, Evolution Equations for QCD String Operators, Nucl. Phys. B311, 541 (1989).
- V. M. Belyaev and B. Y. Blok, Charmed baryons in quantum chromodynamics, Z. Phys. C 30, 151 (1986).
- D. Antonov and J. E. F. T. Ribeiro, Quark condensate for various heavy flavors, Eur. Phys. J. C 72, 2179 (2012).
- S. Navas et al., Review of particle physics, Phys. Rev. D 110, 030001 (2024).
- B. L. Ioffe, QCD at low energies, Prog. Part. Nucl. Phys. 56, 232 (2006).
- S. Narison, and from Heavy Quarkonia, Nucl. Part. Phys. Proc. 300–302, 153 (2018).
- J. Rohrwild, Determination of the magnetic susceptibility of the quark condensate using radiative heavy meson decays, J. High Energy Phys. 09 (2007) 073.
- U. Özdem, Investigating the underlying structure of vector hidden-charm tetraquark states via their electromagnetic characteristics, Phys. Rev. D 111, 054009 (2025).
- U. Özdem, Unveiling the underlying structure of axial-vector bottom-charm tetraquarks in the light of their magnetic moments, J. High Energy Phys. 05 (2024) 301.
- U. Özdem and K. Azizi, Electromagnetic properties of vector doubly charmed tetraquark states, Phys. Rev. D 109, 114019 (2024).
- K. Azizi and U. Özdem, Exploring the magnetic dipole moments of and states in the framework of QCD light-cone sum rules, J. High Energy Phys. 03 (2023) 166.
- U. Özdem, Deciphering the nature of pentaquarks in the light of their electromagnetic multipole moments, J. High Energy Phys. 07 (2026) 004.