- Physical Review Journals
All JournalsPhysics Magazine

Physical Review Research

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
  • Letter
  • Open Access

Signatures of jet drift in quark-gluon plasma hard-probe observables

Joseph Bahder1,*, Hasan Rahman1,†, Matthew D. Sievert1,‡, and Ivan Vitev2,§

  • *Contact author: jbahder@nmsu.edu
  • †Contact author: hrrahman@nmsu.edu
  • ‡Contact author: msievert@nmsu.edu
  • §Contact author: ivitev@lanl.gov
PDF

Phys. Rev. Research 8, L012016 – Published 16 January, 2026

DOI: https://doi.org/10.1103/8yzj-2l5c

Abstract

Hard-probe tomography of the quark-gluon plasma (QGP) in heavy ion collisions has long been a preeminent goal of the high-energy nuclear physics program. In service of this goal, the isotropic modification of jets and high-energy hadrons has been studied in great detail at the leading-power (eikonal) level, with effects originating from sub-eikonal O(μ/E) anisotropic interactions presumed to be small. We present the first investigation of sub-eikonal, collective-flow-induced asymmetric jet broadening (jet drift) in event-by-event s=5.02 TeV PbPb collisions at the Large Hadron Collider using the Anisotropic Parton Evolution computational framework. We show that jet drift imparts a significant enhancement of elliptic flow (v2) larger than the experimental resolution and increases the mean acoplanarity for low- and intermediate-energy particles (pT<10 GeV). Importantly, these modifications to hard-probe observables are shown to survive averaging over events and collision geometry. They couple to the collective flow of the medium seen by the jet and encode information about the QGP dynamics inaccessible to studies considering only isotropic, eikonal-level effects.

View figure in article

Physics Subject Headings (PhySH)

Article Text

References (63)

  1. M. Connors, C. Nattrass, R. Reed, and S. Salur, Jet measurements in heavy ion physics, Rev. Mod. Phys. 90, 025005 (2018).
  2. I. Vitev and M. Gyulassy, High pT tomography of d+ Au and Au+Au at SPS, RHIC, and LHC, Phys. Rev. Lett. 89, 252301 (2002).
  3. J. Noronha-Hostler, B. Betz, J. Noronha, and M. Gyulassy, Event-by-event hydrodynamics + jet energy loss: A solution to the RAA⊗v2 puzzle, Phys. Rev. Lett. 116, 252301 (2016).
  4. D. Molnar and D. Sun, High-PT suppression and elliptic flow from radiative energy loss with realistic bulk medium expansion, arXiv:1305.1046.
  5. W. Zhao, W. Ke, W. Chen, T. Luo, and X.-N. Wang, From hydrodynamics to jet quenching, coalescence, and hadron cascade: A coupled approach to solving the RAA⊗v2 puzzle, Phys. Rev. Lett. 128, 022302 (2022).
  6. X. Zhang and J. Liao, Jet quenching and its azimuthal anisotropy in AA and possibly high multiplicity pA and dA collisions, arXiv:1311.5463.
  7. B. Z. Kopeliovich, J. Nemchik, I. K. Potashnikova, and I. Schmidt, Quenching of high-PT Hadrons: Energy loss vs color transparency, Phys. Rev. C 86, 054904 (2012).
  8. C. Andres, N. Armesto, H. Niemi, R. Paatelainen, and C. A. Salgado, Jet quenching as a probe of the initial stages in heavy-ion collisions, Phys. Lett. B 803, 135318 (2020).
  9. A. Hayrapetyan et al. (CMS Collaboration), Overview of high-density QCD studies with the CMS experiment at the LHC, Phys. Rept. 1115, 219 (2025).
  10. S. Acharya et al. (ALICE Collaboration), Observation of medium-induced yield enhancement and acoplanarity broadening of low-pT jets from measurements in pp and central Pb-Pb collisions at √sNN = 5.02 TeV, Phys. Rev. Lett. 133, 022301 (2024).
  11. A. V. Sadofyev, M. D. Sievert, and I. Vitev, Ab initio coupling of jets to collective flow in the opacity expansion approach, Phys. Rev. D 104, 094044 (2021).
  12. B. Schenke, C. Gale, and S. Jeon, MARTINI: An event generator for relativistic heavy-ion collisions, Phys. Rev. C 80, 054913 (2009).
  13. W. Chen, S. Cao, T. Luo, L.-G. Pang, and X.-N. Wang, Medium modification of γ-jet fragmentation functions in Pb+Pb collisions at LHC, Phys. Lett. B 810, 135783 (2020).
  14. L. Antiporda, J. Bahder, H. Rahman, and M. D. Sievert, Jet drift and collective flow in heavy-ion collisions, Phys. Rev. D 105, 054025 (2022).
  15. X.-N. Wang and M. Gyulassy, HIJING: A Monte Carlo model for multiple jet production in pp, pA and AA collisions, Phys. Rev. D 44, 3501 (1991).
  16. I. P. Lokhtin, L. V. Malinina, S. V. Petrushanko, A. M. Snigirev, I. Arsene, and K. Tywoniuk, Heavy ion event generator HYDJET++ (HYDrodynamics plus JETs), Comput. Phys. Commun. 180, 779 (2009).
  17. K. Zapp, J. Stachel, and U. A. Wiedemann, JEWEL—a Monte Carlo Model for Jet Quenching, PoS High-pT physics09, 022 (2009).
  18. D. Zigic, I. Salom, J. Auvinen, P. Huovinen, and M. Djordjevic, DREENA—A framework as a QGP tomography tool, Front. Phys. 10, 957019 (2022).
  19. J. Casalderrey-Solana, D. C. Gulhan, J. G. Milhano, D. Pablos, and K. Rajagopal, A hybrid strong/weak coupling approach to jet quenching, J. High Energy Phys. 10 (2014) 019 ; Erratum 09 (2015) 175.
  20. J. H. Putschke et al., The JETSCAPE framework, arXiv:1903.07706.
  21. N. Armesto, C. A. Salgado, and U. A. Wiedemann, Measuring the collective flow with jets, Phys. Rev. Lett. 93, 242301 (2004).
  22. J. S. Moreland, J. E. Bernhard, and S. A. Bass, Bayesian calibration of a hybrid nuclear collision model using p-Pb and Pb-Pb data at energies available at the CERN Large Hadron Collider, Phys. Rev. C 101, 024911 (2020).
  23. J. S. Moreland, J. E. Bernhard, and S. A. Bass, Alternative ansatz to wounded nucleon and binary collision scaling in high-energy nuclear collisions, Phys. Rev. C 92, 011901 (2015).
  24. J. S. Moreland, J. E. Bernhard, W. Ke, and S. A. Bass, Flow in small and large quark-gluon plasma droplets: The role of nucleon substructure, Nucl. Phys. A 967, 361 (2017).
  25. H. Song, S. A. Bass, and U. Heinz, Viscous QCD matter in a hybrid hydrodynamic+Boltzmann approach, Phys. Rev. C 83, 024912 (2011).
  26. S. A. Bass et al., Microscopic models for ultrarelativistic heavy ion collisions, Prog. Part. Nucl. Phys. 41, 255 (1998).
  27. When discussing the power counting of the eikonal expansion, we refer to the parton energy E=(pTp)2+m2coshy rather than pTp to avoid confusion with drift transverse to the jet axis. For light particle production at mid rapidity y,m≈0, the two are equivalent: E≈pTp.
  28. C. Bierlich et al., A comprehensive guide to the physics and usage of PYTHIA 8.3, SciPost Phys. Codeb. 2022, 8 (2022).
  29. J. E. Bernhard, J. S. Moreland, S. A. Bass, J. Liu, and U. Heinz, Applying Bayesian parameter estimation to relativistic heavy-ion collisions: Simultaneous characterization of the initial state and quark-gluon plasma medium, Phys. Rev. C 94, 024907 (2016).
  30. V. Khachatryan et al. (CMS Collaboration), Charged-particle nuclear modification factors in PbPb and pPb collisions at sNN=5.02 TeV, J. High Energy Phys. 09 (2017) 039.
  31. Y. He, I. Vitev, and B.-W. Zhang, O(αs3) Analysis of inclusive jet and di-jet production in heavy ion reactions at the large Hadron collider, Phys. Lett. B 713, 224 (2012).
  32. M. Gyulassy, P. Levai, and I. Vitev, Reaction operator approach to multiple elastic scatterings, Phys. Rev. D 66, 014005 (2002).
  33. J.-W. Qiu and I. Vitev, Resummed QCD power corrections to nuclear shadowing, Phys. Rev. Lett. 93, 262301 (2004).
  34. M. Gyulassy and X.-N. Wang, Multiple collisions and induced gluon bremsstrahlung in QCD, Nucl. Phys. B 420, 583 (1994).
  35. M. D. Sievert, I. Vitev, and B. Yoon, A complete set of in-medium splitting functions to any order in opacity, Phys. Lett. B 795, 502 (2019).
  36. M. Gyulassy, I. Vitev, and X. N. Wang, High PT azimuthal asymmetry in noncentral A+A at RHIC, Phys. Rev. Lett. 86, 2537 (2001).
  37. C. Faraday and W. Horowitz, Energy loss in small collision systems, PoS HardProbes2023, 131 (2024).
  38. M. Gyulassy, P. Levai, and I. Vitev, Reaction operator approach to non-Abelian energy loss, Nucl. Phys. B 594, 371 (2001).
  39. I. Kolbe and W. A. Horowitz, Short path length corrections to Djordjevic-Gyulassy-Levai-Vitev energy loss, Phys. Rev. C 100, 024913 (2019).
  40. A. B. Migdal, Bremsstrahlung and pair production in condensed media at high-energies, Phys. Rev. 103, 1811 (1956).
  41. L. D. Landau and I. Pomeranchuk, Limits of applicability of the theory of bremsstrahlung electrons and pair production at high-energies, Dokl. Akad. Nauk Ser. Fiz. 92, 535 (1953).
  42. E. Braaten and M. H. Thoma, Energy loss of a heavy quark in the quark-gluon plasma, Phys. Rev. D 44, R2625(R) (1991).
  43. M. H. Thoma and M. Gyulassy, Quark damping and energy loss in the high temperature QCD, Nucl. Phys. B 351, 491 (1991).
  44. M. Djordjevic, Collisional energy loss in a finite size QCD matter, Phys. Rev. C 74, 064907 (2006).
  45. J. A. Barata, A. V. Sadofyev, and C. A. Salgado, Jet broadening in dense inhomogeneous matter, Phys. Rev. D 105, 114010 (2022).
  46. C. Andres, F. Dominguez, A. V. Sadofyev, and C. A. Salgado, Jet broadening in flowing matter: Resummation, Phys. Rev. D 106, 074023 (2022).
  47. J. A. Barata, X. Mayo López, A. V. Sadofyev, and C. A. Salgado, Medium induced gluon spectrum in dense inhomogeneous matter, Phys. Rev. D 108, 034018 (2023).
  48. M. V. Kuzmin, X. Mayo López, J. Reiten, and A. V. Sadofyev, Jet quenching in anisotropic flowing matter, Phys. Rev. D 109, 014036 (2024).
  49. M. V. Kuzmin and X. Mayo López, Gluon radiation inside a flowing medium, arXiv:2406.14628.
  50. C. Markert, R. Bellwied, and I. Vitev, Formation and decay of hadronic resonances in the QGP, Phys. Lett. B 669, 92 (2008).
  51. E. Moffat, W. Melnitchouk, T. C. Rogers, and N. Sato (Jefferson Lab Angular Momentum (JAM) Collaboration), Simultaneous Monte Carlo analysis of parton densities and fragmentation functions, Phys. Rev. D 104, 016015 (2021).
  52. A. Buckley, J. Ferrando, S. Lloyd, K. Nordström, B. Page, M. Rüfenacht, M. Schönherr, and G. Watt, LHAPDF6: Parton density access in the LHC precision era, Eur. Phys. J. C 75, 132 (2015).
  53. V. Greco, C. M. Ko, and P. Levai, Parton coalescence and anti-proton/pion anomaly at RHIC, Phys. Rev. Lett. 90, 202302 (2003).
  54. L. S. Moriggi, E. S. Rocha, and M. V. T. Machado, Study of the azimuthal asymmetry in heavy ion collisions combining initial state momentum orientation and final state collective effects, Phys. Rev. D 108, 074013 (2023).
  55. A. Bilandzic, Anisotropic flow measurements in ALICE at the large hadron collider, Ph.D. thesis, University of Utrecht, 2012.
  56. A. M. Sirunyan et al. (CMS Collaboration), Azimuthal anisotropy of charged particles with transverse momentum up to 100 GeV/c in PbPb collisions at sNN=5.02TeV, Phys. Lett. B 776, 195 (2018).
  57. W. Ke, J. Terry, and I. Vitev, Anisotropic jet broadening and jet shape, JHEP 07, 097 (2025).
  58. J. A. Barata, J. G. Milhano, and A. V. Sadofyev, Picturing QCD jets in anisotropic matter: From jet shapes to energy energy correlators, Eur. Phys. J. C 84, 174 (2024).
  59. R. Pordes, D. Petravick, B. Kramer, D. Olson, M. Livny, A. Roy, P. Avery, K. Blackburn, T. Wenaus, F. Würthwein, I. Foster, R. Gardner, M. Wilde, A. Blatecky, J. McGee, and R. Quick, The open science grid, J. Phys. Conf. Ser. 78, 012057 (2007).
  60. I. Sfiligoi, D. C. Bradley, B. Holzman, P. Mhashilkar, S. Padhi, and F. Wurthwein, The Pilot Way to Grid Resources Using glideinWMS, in 2009 WRI World Congress on Computer Science and Information Engineering (IEEE, New York, 2009), pp. 428–432.
  61. OSG, OSPool, https://osg-htc.org/acknowledging.
  62. OSG, Open Science Data Federation, https://osdf.osg-htc.org/ (2025).
  63. J. Bahder, Anisotropic Parton Evolution (APE), https://github.com/Jopacabra/ape (2025).

Outline

Information

Phys. Rev. Research 8, L012016– Published 16 January, 2026
  • Received 18 February 2025
  • Accepted 31 August 2025
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.

Published by the American Physical Society

Sign In to Your Journals Account

Filter

Filter

Article Lookup

Enter a citation