- 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

Parton spin correlations and CP properties in Higgs boson decay at future lepton colliders

Yi-Lin Wang1,2,3,*, Jun Gao4,†, Ying-Ying Li3,‡, and Hua Xing Zhu5,6,§

  • *Contact author: wangyilin@mail.ustc.edu.cn
  • †Contact author: jung49@sjtu.edu.cn
  • ‡Contact author: liyingying@ihep.ac.cn
  • §Contact author: zhuhx@pku.edu.cn
PDF

Phys. Rev. D 114, 016006 – Published 6 July, 2026

DOI: https://doi.org/10.1103/1ksd-rlr9

Abstract

We present a phenomenological study of partonic spin correlations and CP properties in H→gg decay channel at future lepton colliders. We investigate two classes of observables: Lund observable defined based on subjets and four-point energy-energy correlator (E4C) between particles inside two jets. Our results show that the E4C with energy weighted to the power of n=4 achieves the strongest sensitivity to the spin correlations of gluons from Higgs boson decay. Under the assumption of ideal identification of different gluon splitting modes, we estimate that future lepton colliders operating at s=240  GeV with an integrated luminosities of 5.6  ab−1 can successfully probe gluon spin correlations, while 20  ab−1 of data can probe the CP-mixing angle in the Hgg coupling to ≲0.03π using E4C. We outline strategies for extending this framework to realistic detector-level analyses, which can provide a new pathway for the precision test of Standard Model and searches for new physics.

View figure in article

Physics Subject Headings (PhySH)

Article Text

References (46)

  1. A. J. Barr, M. Fabbrichesi, R. Floreanini, E. Gabrielli, and L. Marzola, Quantum entanglement and Bell inequality violation at colliders, Prog. Part. Nucl. Phys. 139, 104134 (2024).
  2. Y. Fang, C. Gao, Y.-Y. Li, J. Shu, Y. Wu, H. Xing, B. Xu, L. Xu, and C. Zhou, Quantum frontiers in high energy physics, Sci. China Phys. Mech. Astron. 68, 260301 (2025).
  3. G. Aad et al. (ATLAS Collaboration), Measurement of spin correlation in top-antitop quark events and search for top squark pair production in pp collisions at s=8  TeV using the ATLAS detector, Phys. Rev. Lett. 114, 142001 (2015).
  4. A. Kobakhidze, L. Wu, and J. Yue, Anomalous top-Higgs couplings and top polarisation in single top and Higgs associated production at the LHC, J. High Energy Phys. 10 (2014) 100.
  5. W. Bernreuther, D. Heisler, and Z.-G. Si, A set of top quark spin correlation and polarization observables for the LHC: standard model predictions and new physics contributions, J. High Energy Phys. 12 (2015) 026.
  6. F. Arco, T. Biekötter, P. Stylianou, and G. Weiglein, Top-quark spin correlations as a tool to distinguish pseudoscalar A→ZH and scalar H→ZA signatures in Ztt¯ final states at the LHC, J. High Energy Phys. 06 (2025) 170.
  7. F. Maltoni, C. Severi, S. Tentori, and E. Vryonidou, Quantum detection of new physics in top-quark pair production at the LHC, J. High Energy Phys. 03 (2024) 099.
  8. G. Aad et al. (ATLAS Collaboration), Observation of quantum entanglement with top quarks at the ATLAS detector, Nature (London) 633, 542 (2024).
  9. CMS Collaboration, Observation of quantum entanglement in top quark pair production in proton–proton collisions at s=13  TeV, Rep. Prog. Phys. 87, 117801 (2024).
  10. M. Dasgupta, F. A. Dreyer, K. Hamilton, P. F. Monni, G. P. Salam, and G. Soyez, Parton showers beyond leading logarithmic accuracy, Phys. Rev. Lett. 125, 052002 (2020).
  11. J. R. Forshaw, J. Holguin, and S. Plätzer, Building a consistent parton shower, J. High Energy Phys. 09 (2020) 014.
  12. Z. Nagy and D. E. Soper, Summations of large logarithms by parton showers, Phys. Rev. D 104, 054049 (2021).
  13. A. Karlberg, G. P. Salam, L. Scyboz, and R. Verheyen, Spin correlations in final-state parton showers and jet observables, Eur. Phys. J. C 81, 681 (2021).
  14. F. Herren, S. Höche, F. Krauss, D. Reichelt, and M. Schoenherr, A new approach to color-coherent parton evolution, J. High Energy Phys. 10 (2022) 091.
  15. C. T. Preuss, A partitioned dipole-antenna shower with improved transverse recoil, J. High Energy Phys. 07 (2024) 161.
  16. B. Assi and S. Höche, New approach to QCD final-state evolution in processes with massive partons, Phys. Rev. D 109, 114008 (2024).
  17. C. W. Bauer, W. A. de Jong, B. Nachman, and D. Provasoli, Quantum algorithm for high energy physics simulations, Phys. Rev. Lett. 126, 062001 (2021).
  18. K. Bepari, S. Malik, M. Spannowsky, and S. Williams, Quantum walk approach to simulating parton showers, Phys. Rev. D 106, 056002 (2022).
  19. C. W. Bauer, S. Chigusa, and M. Yamazaki, Quantum parton shower with kinematics, Phys. Rev. A 109, 032432 (2024).
  20. H. Chen, I. Moult, and H. X. Zhu, Quantum interference in jet substructure from spinning gluons, Phys. Rev. Lett. 126, 112003 (2021).
  21. X. L. Li, X. Liu, F. Yuan, and H. X. Zhu, Illuminating nucleon-gluon interference via calorimetric asymmetry, Phys. Rev. D 108, L091502 (2023).
  22. Z.-B. Kang, K. Lee, D. Y. Shao, and F. Zhao, Probing transverse momentum dependent structures with azimuthal dependence of energy correlators, J. High Energy Phys. 03 (2023) 153.
  23. H. Mäntysaari, Y. Tawabutr, and X.-B. Tong, Nucleon energy correlators for the odderon, Phys. Rev. D 112, 114027 (2025).
  24. Y. Huang, X.-B. Tong, and H.-L. Wang, Nucleon energy correlators as a probe of light-quark dipole operators at the EIC, Phys. Rev. Lett. 136, 131902 (2026).
  25. Y.-K. Song, S.-Y. Wei, L. Yang, and J. Zhou, Gluon polarimetry with energy-energy correlators, Phys. Rev. Lett. 136, 131901 (2026).
  26. J. Gao, H. T. Li, and Y. J. Zhu, Energy correlators resolving proton spin, Phys. Rev. D 113, 034028 (2026).
  27. Q.-H. Cao, Z. Yu, C. P. Yuan, S. Zhang, and H. X. Zhu, Collins-type fragmentation energy correlator in semi-inclusive deep inelastic lepton-hadron scattering, J. High Energy Phys. 02 (2026) 244.
  28. M.-S. Gao, Z.-B. Kang, W. Li, and D. Y. Shao, Accessing nucleon transversity with one-point energy correlators, Phys. Rev. Lett. 136, 151902 (2026).
  29. I. Moult and H. X. Zhu, Energy correlators: A journey from theory to experiment, arXiv:2506.09119.
  30. A. Abada et al., FCC physics opportunities, Eur. Phys. J. C 79, 474 (2019).
  31. M. Dong et al. (CEPC Study Group), CEPC conceptual design report: Volume 2—physics & detector, arXiv:1811.10545.
  32. H. Chen, I. Moult, and H. X. Zhu, Quantum interference in jet substructure from spinning gluons, Phys. Rev. Lett. 126, 112003 (2021).
  33. S. Catani and M. Grazzini, Infrared factorization of tree level QCD amplitudes at the next-to-next-to-leading order and beyond, Nucl. Phys. B570, 287 (2000).
  34. V. N. Gribov and L. N. Lipatov, Deep inelastic e p scattering in perturbation theory, Sov. J. Nucl. Phys. 15, 438 (1972).
  35. Y. L. Dokshitzer, Calculation of the structure functions for deep inelastic scattering and e+e− annihilation by perturbation theory in quantum chromodynamics., Sov. Phys. JETP 46, 641 (1977).
  36. G. Altarelli and G. Parisi, Asymptotic freedom in parton language, Nucl. Phys. B126, 298 (1977).
  37. A. J. Larkoski, D. Neill, and I. W. Stewart, Soft theorems from effective field theory, J. High Energy Phys. 06 (2014) 077.
  38. L. Li, Y.-Y. Li, T. Liu, and S.-J. Xu, Learning physics at future e−e+ colliders with machine, J. High Energy Phys. 10 (2020) 018.
  39. H. Cheng et al. (CEPC Physics Study Group), The physics potential of the CEPC. Prepared for the US Snowmass Community Planning Exercise (Snowmass 2021), in Snowmass 2021 (2022), arXiv:2205.08553.
  40. , Measurement of gluon spin effect in parton splittings, CERN Technical Report No. CMS-PAS-SMP-25-006, 2025.
  41. J. Kley, T. Theil, E. Venturini, and A. Weiler, Electric dipole moments at one-loop in the dimension-6 SMEFT, Eur. Phys. J. C 82, 926 (2022).
  42. U. Haisch and A. Hala, Bounds on CP-violating Higgs-gluon interactions: The case of vanishing light-quark Yukawa couplings, J. High Energy Phys. 11 (2019) 117.
  43. V. Cirigliano, A. Crivellin, W. Dekens, J. de Vries, M. Hoferichter, and E. Mereghetti, CP violation in Higgs-gauge interactions: From tabletop experiments to the LHC, Phys. Rev. Lett. 123, 051801 (2019).
  44. H. Bahl, E. Fuchs, M. Hannig, and M. Menen, Classifying the CP properties of the ggH coupling in H+2j production, SciPost Phys. Core 8, 006 (2025).
  45. C. Englert, P. Galler, A. Pilkington, and M. Spannowsky, Approaching robust EFT limits for CP-violation in the Higgs sector, Phys. Rev. D 99, 095007 (2019).
  46. F. U. Bernlochner, C. Englert, C. Hays, K. Lohwasser, H. Mildner, A. Pilkington, D. D. Price, and M. Spannowsky, Angles on CP-violation in Higgs boson interactions, Phys. Lett. B 790, 372 (2019).

Outline

Information

Phys. Rev. D 114, 016006– Published 6 July, 2026
  • Received 9 February 2026
  • Accepted 12 June 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