- Open Access
Existence of the and three-body molecular states
Phys. Rev. D 114, 014048 – Published 22 July, 2026
DOI: https://doi.org/10.1103/xxsq-d5sm
Abstract
We investigate the existence of the three-body molecular state composed of within the one-boson-exchange model. A major challenge is that while the pseudoscalar-meson couplings are well determined, the couplings for scalar- and vector-meson exchanges render significant model dependence. To ensure the reliability of our predictions and reduce model dependence, we recalibrate the coupling constants of the one-boson-exchange model. We treat the pole position of , or equivalently the scalar -exchange coupling constant, as the only unknown parameter. The coupling constants for the vector and exchanges are determined by the pole positions of the well-established states and . We demonstrate that these parameter sets also successfully describe the without further tuning. For the three-body system, our results indicate that an three-body molecular bound state exists when is a virtual state located within approximately of the threshold. Furthermore, we extend our analysis to the complex energy plane using the complex scaling method to search for molecular resonances, though no evidence of resonances is found in considered channels. We also apply this formalism to the bottom analog system. In this sector, the conditions for the existence of a three-body bound state are more relaxed, as a virtual state located within below the threshold suffices, although three-body molecular resonances remain absent. We suggest that future experiments precisely measure the pole position of or search for the three-body bound state in and channels, as these efforts would mutually illuminate the nature of the associated states.
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References (117)
- H.-X. Chen, W. Chen, X. Liu, and S.-L. Zhu, The hidden-charm pentaquark and tetraquark states, Phys. Rep. 639, 1 (2016).
- A. Esposito, A. Pilloni, and A. D. Polosa, Multiquark resonances, Phys. Rep. 668, 1 (2017).
- R. F. Lebed, R. E. Mitchell, and E. S. Swanson, Heavy-quark QCD exotica, Prog. Part. Nucl. Phys. 93, 143 (2017).
- 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).
- S. L. Olsen, T. Skwarnicki, and D. Zieminska, Nonstandard heavy mesons and baryons: Experimental evidence, Rev. Mod. Phys. 90, 015003 (2018).
- M. Karliner, J. L. Rosner, and T. Skwarnicki, Multiquark states, Annu. Rev. Nucl. Part. Sci. 68, 17 (2018).
- 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).
- 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).
- 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).
- 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).
- T.-W. Wu, Y.-W. Pan, M.-Z. Liu, and L.-S. Geng, Multi-hadron molecules: Status and prospect, Sci. Bull. 67, 1735 (2022).
- S. K. Choi et al. (Belle Collaboration), Observation of a narrow charmonium-like state in exclusive decays, Phys. Rev. Lett. 91, 262001 (2003).
- M. Ablikim et al. (BESIII Collaboration), Observation of a charged charmoniumlike structure in at , Phys. Rev. Lett. 110, 252001 (2013).
- Z. Q. Liu et al. (Belle Collaboration), Study of and observation of a charged charmoniumlike state at Belle, Phys. Rev. Lett. 110, 252002 (2013); 111, 019901(E) (2013).
- R. Aaij et al. (LHCb Collaboration), A model-independent study of resonant structure in decays, Phys. Rev. Lett. 125, 242001 (2020).
- R. Aaij et al. (LHCb Collaboration), Amplitude analysis of the decay, Phys. Rev. D 102, 112003 (2020).
- R. Aaij et al. (LHCb Collaboration), Observation of new charmonium or charmoniumlike states in decays, Phys. Rev. Lett. 133, 131902 (2024).
- R. Aaij et al. (LHCb Collaboration), Observation of an exotic narrow doubly charmed tetraquark, Nat. Phys. 18, 751 (2022).
- R. Aaij et al. (LHCb Collaboration), Study of the doubly charmed tetraquark , Nat. Commun. 13, 3351 (2022).
- S. Navas et al. (Particle Data Group), Review of particle physics, Phys. Rev. D 110, 030001 (2024).
- Q.-H. Shen and J.-J. Xie, Faddeev fixed-center approximation to the , , and systems, Phys. Rev. D 107, 034019 (2023).
- X. Zhang, C. Hanhart, U.-G. Meißner, and J.-J. Xie, Remarks on non-perturbative three–body dynamics and its application to the system, Eur. Phys. J. A 58, 20 (2022).
- T.-W. Wu, Y.-W. Pan, M.-Z. Liu, S.-Q. Luo, L.-S. Geng, and X. Liu, Discovery of the doubly charmed state implies a triply charmed hexaquark state, Phys. Rev. D 105, L031505 (2022).
- S.-Q. Luo, T.-W. Wu, M.-Z. Liu, L.-S. Geng, and X. Liu, Triple-charm molecular states composed of and , Phys. Rev. D 105, 074033 (2022).
- M. Bayar, A. Martinez Torres, K. P. Khemchandani, R. Molina, and E. Oset, Exotic states with triple charm, Eur. Phys. J. C 83, 46 (2023).
- Y.-W. Pan, T.-W. Wu, M.-Z. Liu, and L.-S. Geng, Hadronic molecules composed of a doubly charmed tetraquark state and a charmed meson, Eur. Phys. J. C 82, 908 (2022).
- P. G. Ortega, Exploring the Efimov effect in the system, Phys. Rev. D 110, 034015 (2024).
- H.-L. Fu, Y.-H. Lin, F.-K. Guo, H.-W. Hammer, U.-G. Meißner, A. Rusetsky, and X. Zhang, Exploring Efimov states in and three-body systems, J. High Energy Phys. 07 (2025) 081.
- Y. Tan, X. Liu, X. Chen, Y. Yang, H. Huang, and J. Ping, Dynamical study of and systems at quark level, Phys. Rev. D 110, 016005 (2024).
- M. P. Valderrama, and three-body systems, Phys. Rev. D 98, 034017 (2018).
- J. M. Dias, L. Roca, and S. Sakai, Prediction of new states from three-body interactions, Phys. Rev. D 97, 056019 (2018).
- L. Ma, Q. Wang, and U.-G. Meißner, Trimeson bound state via a delocalized bond, Phys. Rev. D 100, 014028 (2019).
- L. Ma, Q. Wang, and U.-G. Meißner, Double heavy tri-hadron bound state via delocalized bond, Chin. Phys. C 43, 014102 (2019).
- X.-L. Ren, B. B. Malabarba, L.-S. Geng, K. P. Khemchandani, and A. Martínez Torres, mesons with hidden charm arising from and dynamics, Phys. Lett. B 785, 112 (2018).
- X.-L. Ren and Z.-F. Sun, Possible bound states with hidden bottom from systems, Phys. Rev. D 99, 094041 (2019).
- T.-W. Wu, M.-Z. Liu, L.-S. Geng, E. Hiyama, and M. P. Valderrama, , , and molecules–understanding the nature of the , Phys. Rev. D 100, 034029 (2019).
- Z.-Y. Di and Z.-G. Wang, Analysis of the system with QCD sum rules, Adv. High Energy Phys. 2019, 8958079 (2019).
- N. Ikeno, M. Bayar, and E. Oset, Molecular states of nature, Phys. Rev. D 107, 034006 (2023).
- Z. Zhang, X.-Y. Hu, G. He, J. Liu, J.-A. Shi, B.-N. Lu, and Q. Wang, Binding of the three-hadron system from the lattice effective field theory, Phys. Rev. D 111, 036002 (2025).
- Q.-Y. Zhai, R. Molina, E. Oset, and L.-S. Geng, Study of the exotic three-body system, Phys. Rev. D 111, 034039 (2025).
- X.-L. Ren, K. P. Khemchandani, and A. Martínez Torres, Heavy mesons with open charm from interactions, Eur. Phys. J. C 84, 1297 (2024).
- Y.-W. Pan, J.-X. Lu, E. Hiyama, L.-S. Geng, and A. Hosaka, Effect of a repulsive three-body interaction on the molecule, Phys. Rev. D 111, 114006 (2025).
- D. L. Canham, H. W. Hammer, and R. P. Springer, On the scattering of and mesons off the X(3872), Phys. Rev. D 80, 014009 (2009).
- Y.-H. Lin, E. Wilbring, H.-L. Fu, H.-W. Hammer, and U.-G. Meißner, Three-body universality in the meson sector, J. Phys. G 52, 105005 (2025).
- A. Martinez Torres, K. P. Khemchandani, L. Roca, and E. Oset, Few-body systems consisting of mesons, Few Body Syst. 61, 35 (2020).
- 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).
- R. Molina, T. Branz, and E. Oset, A new interpretation for the and the prediction of novel exotic charmed mesons, Phys. Rev. D 82, 014010 (2010).
- H.-X. Chen, W. Chen, R.-R. Dong, and N. Su, and : Hadronic molecules or compact tetraquarks, Chin. Phys. Lett. 37, 101201 (2020).
- J. He and D.-Y. Chen, Molecular picture for and , Chin. Phys. C 45, 063102 (2021).
- M.-Z. Liu, J.-J. Xie, and L.-S. Geng, as a molecular state, Phys. Rev. D 102, 091502 (2020).
- M.-W. Hu, X.-Y. Lao, P. Ling, and Q. Wang, and its heavy quark spin partners in molecular picture, Chin. Phys. C 45, 021003 (2021).
- S. S. Agaev, K. Azizi, and H. Sundu, New scalar resonance as a molecule: Mass and width, J. Phys. G 48, 085012 (2021).
- B. Wang and S.-L. Zhu, How to understand the X(2900)?, Eur. Phys. J. C 82, 419 (2022).
- P. G. Ortega, D. R. Entem, F. Fernandez, and J. Segovia, Novel and candidates in a constituent-quark-model-based meson-meson coupled-channels calculation, Phys. Rev. D 108, 094035 (2023).
- B. Wang, K. Chen, L. Meng, and S.-L. Zhu, Spectrum of the molecular tetraquarks: Unraveling the and , Phys. Rev. D 109, 034027 (2024).
- N. A. Tornqvist, Possible large deuteron—like meson meson states bound by pions, Phys. Rev. Lett. 67, 556 (1991).
- N. A. Tornqvist, From the deuteron to deusons, an analysis of deuteron—like meson meson bound states, Z. Phys. C 61, 525 (1994).
- D. Gamermann, E. Oset, D. Strottman, and M. J. Vicente Vacas, Dynamically generated open and hidden charm meson systems, Phys. Rev. D 76, 074016 (2007).
- Y.-R. Liu, X. Liu, W.-Z. Deng, and S.-L. Zhu, Is really a molecular state?, Eur. Phys. J. C 56, 63 (2008).
- X. Liu, Y.-R. Liu, W.-Z. Deng, and S.-L. Zhu, as a molecular state, Phys. Rev. D 77, 094015 (2008).
- C. E. Thomas and F. E. Close, Is X(3872) a molecule?, Phys. Rev. D 78, 034007 (2008).
- X. Liu, Z.-G. Luo, Y.-R. Liu, and S.-L. Zhu, X(3872) and other possible heavy molecular states, Eur. Phys. J. C 61, 411 (2009).
- G.-J. Ding, J.-F. Liu, and M.-L. Yan, Dynamics of hadronic molecule in one-boson exchange approach and possible heavy flavor molecules, Phys. Rev. D 79, 054005 (2009).
- I. W. Lee, A. Faessler, T. Gutsche, and V. E. Lyubovitskij, X(3872) as a molecular state in a potential model, Phys. Rev. D 80, 094005 (2009).
- Z.-F. Sun, J. He, X. Liu, Z.-G. Luo, and S.-L. Zhu, and as the and molecular states, Phys. Rev. D 84, 054002 (2011).
- N. Li and S.-L. Zhu, Isospin breaking, coupled-channel effects and Diagnosis of X(3872), Phys. Rev. D 86, 074022 (2012).
- N. Li, Z.-F. Sun, X. Liu, and S.-L. Zhu, Coupled-channel analysis of the possible and molecular states, Phys. Rev. D 88, 114008 (2013).
- R. Chen, A. Hosaka, and X. Liu, Heavy molecules and one--exchange model, Phys. Rev. D 96, 116012 (2017).
- M.-Z. Liu, T.-W. Wu, M. Pavon Valderrama, J.-J. Xie, and L.-S. Geng, Heavy-quark spin and flavor symmetry partners of the X(3872) revisited: What can we learn from the one boson exchange model?, Phys. Rev. D 99, 094018 (2019).
- R. Chen and Q. Huang, : A strange hidden-charm tetraquark resonance or not?, Phys. Rev. D 103, 034008 (2021).
- R. Chen, Q. Huang, X. Liu, and S.-L. Zhu, Predicting another doubly charmed molecular resonance , Phys. Rev. D 104, 114042 (2021).
- X.-K. Dong, F.-K. Guo, and B.-S. Zou, A survey of heavy–heavy hadronic molecules, Commun. Theor. Phys. 73, 125201 (2021).
- X.-K. Dong, F.-K. Guo, and B.-S. Zou, A survey of heavy-antiheavy hadronic molecules, Prog. Phys. 41, 65 (2021).
- Z.-Y. Lin, J.-B. Cheng, and S.-L. Zhu, and with the complex scaling method and three-body effect, Phys. Rev. D 110, 054008 (2024).
- J.-B. Cheng, Z.-Y. Lin, and S.-L. Zhu, Double-charm tetraquark under the complex scaling method, Phys. Rev. D 106, 016012 (2022).
- F.-Z. Peng, M.-J. Yan, and M. Pavon Valderrama, Heavy- and light-flavor symmetry partners of the , the , and the from light-meson exchange saturation, Phys. Rev. D 108, 114001 (2023).
- Z.-Y. Lin, J.-Z. Wang, J.-B. Cheng, L. Meng, and S.-L. Zhu, Identification of the as the P-wave resonance, Phys. Rev. Lett. 133, 241903 (2024).
- J.-Z. Wang, Z.-Y. Lin, B. Wang, L. Meng, and S.-L. Zhu, Double pole structures of as the -wave resonances, Phys. Rev. D 110, 114003 (2024).
- J.-Z. Wang, Z.-Y. Lin, J.-B. Cheng, L. Meng, and S.-L. Zhu, Emergence of new heavy quarkoniumlike states: and , arXiv:2505.02742.
- J.-B. Cheng, Z.-Y. Lin, J.-Z. Wang, and S.-L. Zhu, Decoding and : The role of -wave charmed mesons, Phys. Rev. D 113, 096001 (2026).
- H.-X. Zhu, L. Meng, Y. Ma, N. Li, W. Chen, and S.-L. Zhu, Constraining the three-body bound state via the pole, Phys. Rev. D 111, 094022 (2025).
- E. Hiyama, Y. Kino, and M. Kamimura, Gaussian expansion method for few-body systems, Prog. Part. Nucl. Phys. 51, 223 (2003).
- J. Aguilar and J. M. Combes, A class of analytic perturbations for one-body Schroedinger Hamiltonians, Commun. Math. Phys. 22, 269 (1971).
- E. Balslev and J. M. Combes, Spectral properties of many-body Schroedinger operators with dilatation-analytic interactions, Commun. Math. Phys. 22, 280 (1971).
- N. Moiseyev, Quantum theory of resonances: Calculating energies, widths and cross-sections by complex scaling, Phys. Rep. 302, 212 (1998).
- S. Aoyama, T. Myo, K. Katō, and K. Ikeda, The complex scaling method for many-body resonances and its applications to three-body resonances, Prog. Theor. Phys. 116, 1 (2006).
- H. Georgi, Comment on heavy baryon weak form-factors, Nucl. Phys. B348, 293 (1991).
- T. Mannel, W. Roberts, and Z. Ryzak, Baryons in the heavy quark effective theory, Nucl. Phys. B355, 38 (1991).
- A. F. Falk, Hadrons of arbitrary spin in the heavy quark effective theory, Nucl. Phys. B378, 79 (1992).
- M. B. Wise, Chiral perturbation theory for hadrons containing a heavy quark, Phys. Rev. D 45, R2188 (1992).
- T.-M. Yan, H.-Y. Cheng, C.-Y. Cheung, G.-L. Lin, Y. C. Lin, and H.-L. Yu, Heavy quark symmetry and chiral dynamics, Phys. Rev. D 46, 1148 (1992); 55, 5851(E) (1997).
- R. Casalbuoni, A. Deandrea, N. Di Bartolomeo, R. Gatto, F. Feruglio, and G. Nardulli, Phenomenology of heavy meson chiral Lagrangians, Phys. Rep. 281, 145 (1997).
- C. Isola, M. Ladisa, G. Nardulli, and P. Santorelli, Charming penguins in , decays, Phys. Rev. D 68, 114001 (2003).
- M. Albaladejo, F.-K. Guo, C. Hidalgo-Duque, and J. Nieves, : What has been really seen?, Phys. Lett. B 755, 337 (2016).
- A. Pilloni, C. Fernandez-Ramirez, A. Jackura, V. Mathieu, M. Mikhasenko, J. Nys, and A. P. Szczepaniak (JPAC Collaboration), Amplitude analysis and the nature of the , Phys. Lett. B 772, 200 (2017).
- S. X. Nakamura, X. H. Li, H. P. Peng, Z. T. Sun, and X. R. Zhou, Global coupled-channel analysis of processes in to 4.7 GeV, Phys. Rev. D 112, 054027 (2025).
- K. Yu, G.-J. Wang, J.-J. Wu, and Z. Yang, Three-coupled-channel analysis of involving , , and , Phys. Rev. D 110, 114029 (2024).
- Y.-H. Chen, M.-L. Du, and F.-K. Guo, Precise determination of the pole position of the exotic , Sci. China Phys. Mech. Astron. 67, 291011 (2024).
- N. Kalantar-Nayestanaki, E. Epelbaum, J. G. Messchendorp, and A. Nogga, Signatures of three-nucleon interactions in few-nucleon systems, Rep. Prog. Phys. 75, 016301 (2012).
- E. Epelbaum and J. Gegelia, Regularization, renormalization and ‘peratization’ in effective field theory for two nucleons, Eur. Phys. J. A 41, 341 (2009).
- R. Machleidt and D. R. Entem, Chiral effective field theory and nuclear forces, Phys. Rep. 503, 1 (2011).
- U. van Kolck, Few nucleon forces from chiral Lagrangians, Phys. Rev. C 49, 2932 (1994).
- H.-W. Hammer, A. Nogga, and A. Schwenk, Three-body forces: From cold atoms to nuclei, Rev. Mod. Phys. 85, 197 (2013).
- Y.-W. Pan, M.-Z. Liu, and L.-S. Geng, Probing the three-body force in hadronic systems with specific charge parity, Phys. Rev. Lett. 136, 151901 (2026).
- Q. Meng, E. Hiyama, A. Hosaka, M. Oka, P. Gubler, K. U. Can, T. T. Takahashi, and H. S. Zong, Stable double-heavy tetraquarks: Spectrum and structure, Phys. Lett. B 814, 136095 (2021).
- L. Meng, Y.-K. Chen, Y. Ma, and S.-L. Zhu, Tetraquark bound states in constituent quark models: Benchmark test calculations, Phys. Rev. D 108, 114016 (2023).
- J. Carbonell, A. Deltuva, A. C. Fonseca, and R. Lazauskas, Bound state techniques to solve the multiparticle scattering problem, Prog. Part. Nucl. Phys. 74, 55 (2014).
- E. Hiyama, R. Lazauskas, J. Carbonell, and M. Kamimura, Possibility of generating a 4-neutron resonance with a isospin 3-neutron force, Phys. Rev. C 93, 044004 (2016).
- A. Doté, T. Inoue, and T. Myo, Fully coupled-channel study of resonance in a chiral SU(3)-based potential, Phys. Lett. B 784, 405 (2018).
- L. Happ, P. Naidon, and E. Hiyama, Mass ratio dependence of three-body resonance lifetimes in 1D and 3D, Few Body Syst. 65, 38 (2024).
- Y.-K. Chen, L. Meng, Z.-Y. Lin, and S.-L. Zhu, Virtual states in the coupled-channel problems with an improved complex scaling method, Phys. Rev. D 109, 034006 (2024).
- Y.-K. Chen, W.-L. Wu, L. Meng, and S.-L. Zhu, Unified description of the molecular bound states, molecular resonances, and compact tetraquark states in the quark potential model, Phys. Rev. D 109, 014010 (2024).
- Q. Meng, G.-J. Wang, and M. Oka, Mass spectra of full-heavy and double-heavy tetraquark states in the conventional quark model, Phys. Rev. D 111, 014018 (2025).
- Y. Ma, W.-L. Wu, L. Meng, Y.-K. Chen, and S.-L. Zhu, Fully strange tetraquark resonant states as the cousins of X(6900), Phys. Rev. D 110, 074026 (2024).
- W.-L. Wu, Y.-K. Chen, L. Meng, and S.-L. Zhu, Benchmark calculations of fully heavy compact and molecular tetraquark states, Phys. Rev. D 109, 054034 (2024).
- W.-L. Wu, Y. Ma, Y.-K. Chen, L. Meng, and S.-L. Zhu, Doubly heavy tetraquark bound and resonant states, Phys. Rev. D 110, 094041 (2024).