- Physical Review Journals
All JournalsPhysics Magazine

Physical Review D

Reuse & Permissions

It is not necessary to obtain permission to reuse this article or its components as it is available under the terms of the Creative Commons Attribution 4.0 International license. This license permits unrestricted use, distribution, and reproduction in any medium, provided attribution to the author(s) and the published article's title, journal citation, and DOI are maintained. Please note that some figures may have been included with permission from other third parties. It is your responsibility to obtain the proper permission from the rights holder directly for these figures.

Export citation

Export citation

Choose format for download:

Download Citation
  • Open Access

Threshold effects as the origin of Y(4500) observed in e+e−→J/ψK+K−

Xiao-Yun Wang1, Liu-Lin Wang1, Xiao-Hai Liu1,*, and Qiang Zhao2,3,4,†

  • *Contact author: xiaohai.liu@tju.edu.cn
  • †Contact author: zhaoq@ihep.ac.cn
PDF

Phys. Rev. D 113, 014030 – Published 26 January, 2026

DOI: https://doi.org/10.1103/xrdw-64rv

Abstract

The BESIII Collaboration has recently observed a resonant structure Y(4500) in e+e−→J/ψK+K−, whose origin remains unresolved. In this study, we analyze the cross section line shape of e+e−→J/ψK+K− by taking into account the ψ(4415) state and intermediate charmed meson loops. By treating ψ(4415) as both a pure S-wave state and S−D mixed states, and introducing the Zcs(′) resonance, we find that the Y(4500) peak at s=4.5  GeV arises from the triangle singularity mechanism in the Zcs(′)-mediated rescattering processes, supporting its interpretation as a threshold effect rather than a conventional resonance.

View figure in article

Physics Subject Headings (PhySH)

Article Text

References (99)

  1. H. X. Chen, W. Chen, X. Liu, and S. L. Zhu, Phys. Rep. 639, 1 (2016).
  2. H. X. Chen, W. Chen, X. Liu, Y. R. Liu, and S. L. Zhu, Rep. Prog. Phys. 80, 076201 (2017).
  3. A. Esposito, A. Pilloni, and A. D. Polosa, Phys. Rep. 668, 1 (2017).
  4. F. K. Guo, C. Hanhart, U. G. Meißner, Q. Wang, Q. Zhao, and B. S. Zou, Rev. Mod. Phys. 90, 015004 (2018); 94, 029901(E) (2022).
  5. S. L. Olsen, T. Skwarnicki, and D. Zieminska, Rev. Mod. Phys. 90, 015003 (2018).
  6. N. Brambilla, S. Eidelman, C. Hanhart, A. Nefediev, C. P. Shen, C. E. Thomas, A. Vairo, and C. Z. Yuan, Phys. Rep. 873, 1 (2020).
  7. H. X. Chen, W. Chen, X. Liu, Y. R. Liu, and S. L. Zhu, Rep. Prog. Phys. 86, 026201 (2023).
  8. X. H. Liu, G. Li, J. J. Xie, and Q. Zhao, Phys. Rev. D 100, 054006 (2019).
  9. X. H. Liu, M. J. Yan, H. W. Ke, G. Li, and J. J. Xie, Eur. Phys. J. C 80, 1178 (2020).
  10. X. H. Liu and G. Li, Eur. Phys. J. C 76, 455 (2016).
  11. J. J. Wu, X. H. Liu, Q. Zhao, and B. S. Zou, Phys. Rev. Lett. 108, 081803 (2012).
  12. Q. Wang, C. Hanhart, and Q. Zhao, Phys. Rev. Lett. 111, 132003 (2013).
  13. X. H. Liu, Phys. Rev. D 90, 074004 (2014).
  14. X. H. Liu and G. Li, Phys. Rev. D 88, 014013 (2013).
  15. F. K. Guo, C. Hanhart, Q. Wang, and Q. Zhao, Phys. Rev. D 91, 051504 (2015).
  16. M. Mikhasenko, B. Ketzer, and A. Sarantsev, Phys. Rev. D 91, 094015 (2015).
  17. A. P. Szczepaniak, Phys. Lett. B 747, 410 (2015).
  18. F. K. Guo, U. G. Meißner, W. Wang, and Z. Yang, Phys. Rev. D 92, 071502 (2015).
  19. X. H. Liu, M. Oka, and Q. Zhao, Phys. Lett. B 753, 297 (2016).
  20. X. H. Liu, Q. Wang, and Q. Zhao, Phys. Lett. B 757, 231 (2016).
  21. N. N. Achasov, A. A. Kozhevnikov, and G. N. Shestakov, Phys. Rev. D 92, 036003 (2015).
  22. F. K. Guo, U. G. Meißner, J. Nieves, and Z. Yang, Eur. Phys. J. A 52, 318 (2016).
  23. F. Aceti, W. H. Liang, E. Oset, J. J. Wu, and B. S. Zou, Phys. Rev. D 86, 114007 (2012).
  24. F. Aceti, L. R. Dai, and E. Oset, Phys. Rev. D 94, 096015 (2016).
  25. M. Bayar, F. Aceti, F. K. Guo, and E. Oset, Phys. Rev. D 94, 074039 (2016).
  26. L. Roca and E. Oset, Phys. Rev. C 95, 065211 (2017).
  27. X. H. Liu and M. Oka, Nucl. Phys. A954, 352 (2016).
  28. X. H. Liu and M. Oka, Phys. Rev. D 93, 054032 (2016).
  29. Z. Cao and Q. Zhao, Phys. Rev. D 99, 014016 (2019).
  30. X. K. Dong, F. K. Guo, and B. S. Zou, Phys. Rev. Lett. 126, 152001 (2021).
  31. S. X. Nakamura, Phys. Rev. D 103, L111503 (2021).
  32. F. K. Guo, X. H. Liu, and S. Sakai, Prog. Part. Nucl. Phys. 112, 103757 (2020).
  33. R. J. Eden, P. V. Landshoff, D. I. Olive, and J. C. Polkinghorne, The Analytic S-Matrix (Cambridge University Press, Cambridge, England, 1966), ISBN [Amazon][WorldCat].
  34. Y. Guo and C. Z. Yuan, arXiv:2508.20667.
  35. B. Aubert et al. (BABAR Collaboration), Phys. Rev. Lett. 95, 142001 (2005).
  36. Q. He et al. (CLEO Collaboration), Phys. Rev. D 74, 091104 (2006).
  37. C. Z. Yuan et al. (Belle Collaboration), Phys. Rev. Lett. 99, 182004 (2007).
  38. Z. Q. Liu et al. (Belle Collaboration), Phys. Rev. Lett. 110, 252002 (2013); 111, 019901(E) (2013).
  39. M. Ablikim et al. (BESIII Collaboration), Phys. Rev. Lett. 118, 092001 (2017).
  40. Q. Wang and Q. Zhao, Chin. Phys. Lett. 42, 110201 (2025).
  41. M. Ablikim et al. (BESIII Collaboration), Chin. Phys. C 46, 111002 (2022).
  42. M. Ablikim et al. (BESIII Collaboration), Phys. Rev. Lett. 131, 211902 (2023).
  43. M. Ablikim et al. (BESIII Collaboration), Phys. Rev. Lett. 130, 121901 (2023).
  44. M. Ablikim et al. (BESIII Collaboration), Phys. Rev. D 106, 072001 (2022).
  45. Q. Deng, R. H. Ni, Q. Li, and X. H. Zhong, Phys. Rev. D 110, 056034 (2024).
  46. J. Z. Wang and X. Liu, Phys. Rev. D 107, 054016 (2023).
  47. S. D. Liu, Q. Wu, and G. Li, Phys. Rev. D 112, 074036 (2025).
  48. T. W. Chiu et al. (TWQCD Collaboration), Phys. Rev. D 73, 094510 (2006).
  49. Z. G. Wang, Nucl. Phys. B1005, 116580 (2024).
  50. F. Z. Peng, M. J. Yan, M. Sánchez Sánchez, and M. Pavon Valderrama, Phys. Rev. D 107, 016001 (2023).
  51. E. Güngör, H. Sundu, J. Y. Süngü, and E. V. Veliev, Few Body Syst. 64, 53 (2023).
  52. Z. G. Wang, Chin. Phys. C 41, 083103 (2017).
  53. X. K. Dong, F. K. Guo, and B. S. Zou, Progr. Phys. 41, 65 (2021).
  54. M. Ablikim et al. (BESIII Collaboration), Phys. Rev. Lett. 126, 102001 (2021).
  55. L. Meng, B. Wang, and S. L. Zhu, Phys. Rev. D 102, 111502 (2020).
  56. Z. Yang, X. Cao, F. K. Guo, J. Nieves, and M. P. Valderrama, Phys. Rev. D 103, 074029 (2021).
  57. M. C. Du, Q. Wang, and Q. Zhao, arXiv:2011.09225.
  58. R. Chen and Q. Huang, Phys. Rev. D 103, 034008 (2021).
  59. Z. F. Sun and C. W. Xiao, arXiv:2011.09404.
  60. Z. H. Guo and J. A. Oller, Phys. Rev. D 103, 054021 (2021).
  61. M. J. Yan, F. Z. Peng, M. Sánchez Sánchez, and M. Pavon Valderrama, Phys. Rev. D 104, 114025 (2021).
  62. B. D. Wan and C. F. Qiao, Nucl. Phys. B968, 115450 (2021).
  63. Q. N. Wang, W. Chen, and H. X. Chen, Chin. Phys. C 45, 093102 (2021).
  64. Z. G. Wang, Chin. Phys. C 45, 073107 (2021).
  65. X. Jin, Y. Wu, X. Liu, H. Huang, J. Ping, and B. Zhong, Eur. Phys. J. C 81, 1108 (2021).
  66. N. Ikeno, R. Molina, and E. Oset, Phys. Lett. B 814, 136120 (2021).
  67. J. Z. Wang, Q. S. Zhou, X. Liu, and T. Matsuki, Eur. Phys. J. C 81, 51 (2021).
  68. R. Aaij et al. (LHCb Collaboration), Phys. Rev. Lett. 127, 082001 (2021).
  69. M. L. Du, M. Albaladejo, F. K. Guo, and J. Nieves, Phys. Rev. D 105, 074018 (2022).
  70. P. G. Ortega, D. R. Entem, and F. Fernandez, Phys. Lett. B 818, 136382 (2021).
  71. L. Meng, B. Wang, G. J. Wang, and S. L. Zhu, Sci. Bull. 66, 2065 (2021).
  72. N. Ikeno, R. Molina, and E. Oset, Phys. Rev. D 105, 014012 (2022); 106, 099905(E) (2022).
  73. S. Navas et al. (Particle Data Group), Phys. Rev. D 110, 030001 (2024).
  74. U. Özdem and A. K. Y𝚤ld𝚤r𝚤m, Phys. Rev. D 104, 054017 (2021).
  75. R. Casalbuoni, A. Deandrea, N. Di Bartolomeo, R. Gatto, F. Feruglio, and G. Nardulli, Phys. Rep. 281, 145 (1997).
  76. M. B. Wise, Phys. Rev. D 45, R2188 (1992).
  77. G. Burdman and J. F. Donoghue, Phys. Lett. B 280, 287 (1992).
  78. T. M. Yan, H. Y. Cheng, C. Y. Cheung, G. L. Lin, Y. C. Lin, and H. L. Yu, Phys. Rev. D 46, 1148 (1992); 55, 5851(E) (1997).
  79. F. De Fazio, Phys. Rev. D 79, 054015 (2009); 83, 099901(E) (2011).
  80. S. Godfrey and R. Kokoski, Phys. Rev. D 43, 1679 (1991).
  81. T. Mehen and R. P. Springer, Phys. Rev. D 70, 074014 (2004).
  82. T. Bauer and D. R. Yennie, Phys. Lett. 60B, 169 (1976).
  83. G. Li, Q. Zhao, and B. S. Zou, Phys. Rev. D 77, 014010 (2008).
  84. S. Weinberg, Phys. Rev. 130, 776 (1963).
  85. U. G. Meißner and J. A. Oller, Phys. Lett. B 751, 59 (2015).
  86. Z. H. Guo and J. A. Oller, Phys. Lett. B 793, 144 (2019).
  87. J. A. Oller and U. G. Meissner, Phys. Lett. B 500, 263 (2001).
  88. J. A. Oller, Eur. Phys. J. A 28, 63 (2006).
  89. X. W. Kang, Z. H. Guo, and J. A. Oller, Phys. Rev. D 94, 014012 (2016).
  90. R. Brock et al. (CTEQ Collaboration), Rev. Mod. Phys. 67, 157 (1995).
  91. L. D. Landau, Zh. Eksp. Teor. Fiz. 37, 62 (1960).
  92. A. M. Badalian and B. L. G. Bakker, Phys. Rev. D 96, 014030 (2017).
  93. J. Z. Wang, D. Y. Chen, X. Liu, and T. Matsuki, Phys. Rev. D 99, 114003 (2019).
  94. L. Micu, Nucl. Phys. B10, 521 (1969).
  95. A. Le Yaouanc, L. Oliver, O. Pene, and J. C. Raynal, Phys. Rev. D 8, 2223 (1973).
  96. H. G. Blundell and S. Godfrey, Phys. Rev. D 53, 3700 (1996).
  97. T. Barnes, S. Godfrey, and E. S. Swanson, Phys. Rev. D 72, 054026 (2005).
  98. E. S. Ackleh, T. Barnes, and E. S. Swanson, Phys. Rev. D 54, 6811 (1996).
  99. M. Jacob and G. C. Wick, Ann. Phys. (N.Y.) 7, 404 (1959).

Outline

Information

Phys. Rev. D 113, 014030– Published 26 January, 2026
  • Received 30 October 2025
  • Accepted 7 January 2026
Crossmark - Check for updates button
Creative Commons Logo

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.

Published by the American Physical Society

Sign In to Your Journals Account

Filter

Filter

Article Lookup

Enter a citation