Spin-dependent azimuthal asymmetry of coherent J/ψ photoproduction in hadronic PbPb collisions at √(sNN) = 5.36 TeV

@misc{belyaev2026spindependent,
  title = {{Spin-dependent azimuthal asymmetry of coherent J/$ψ$ photoproduction in hadronic PbPb collisions at $\sqrts_\mathrmNN$ = 5.36 TeV}},
  author = {Andrey Belyaev and Arzunik Gevorgyan and Aram Hayrapetyan and Armen Tumasyan and Wolfgang Adam and Lisa Benato and Thomas Bergauer and Marko Dragicevic and Stefan Gundacker and Ali Kaan Guven and Priya Sajid Hussain and Manfred Jeitler and Natascha Krammer and Ang Li and Dietrich Liko and Mark Nicholas Matthewman and Andreas Pfeiffer and Jochen Schieck and Robert Schoefbeck and Maryam Shooshtari and Mangesh Sonawane and Niels van den Bossche and Wolfgang Waltenberger and Claudia Wulz and Tahys Janssen and Daniel Ocampo Henao and Thomas van Laer and Pierre van Mechelen and Donya Ahmadi and Jas Bierkens and Nordin Breugelmans and Soumya Dansana and Alexandre de Moor and Martin Delcourt and Stef Duponcheel and Chirayu Gupta and Felix Johannes Heyen and Yanwen Hong and Kai Kang and Pavlo Kashko and Steven Lowette and Inna Makarenko and Saranya Nandakumar and Jeremi Niedziela and Stefaan Tavernier and Michael Tytgat and Gerrit van Onsem and Senne van Putte and Tiepolo Wybouw and Aya Beshr and Bugra Bilin and Franco Caviglia Roman and Barbara Clerbaux and Aloke Kumar Das and Isabelle de Bruyn and Gilles de Lentdecker and Eliott Ducarme and Hugues Evard and Laurent Favart and Ilia Kalaitzidou},
  howpublished = {HAL},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.04376},
  eprint = {2609.04376},
  archivePrefix = {arXiv},
  url = {https://hal.science/hal-05759122v1},
  note = {CC BY 4.0},
}

TY  - UNPB
TI  - Spin-dependent azimuthal asymmetry of coherent J/ψ photoproduction in hadronic PbPb collisions at √(s_NN) = 5.36 TeV
AU  - Andrey Belyaev
AU  - Arzunik Gevorgyan
AU  - Aram Hayrapetyan
AU  - Armen Tumasyan
AU  - Wolfgang Adam
AU  - Lisa Benato
AU  - Thomas Bergauer
AU  - Marko Dragicevic
AU  - Stefan Gundacker
AU  - Ali Kaan Guven
AU  - Priya Sajid Hussain
AU  - Manfred Jeitler
AU  - Natascha Krammer
AU  - Ang Li
AU  - Dietrich Liko
AU  - Mark Nicholas Matthewman
AU  - Andreas Pfeiffer
AU  - Jochen Schieck
AU  - Robert Schoefbeck
AU  - Maryam Shooshtari
AU  - Mangesh Sonawane
AU  - Niels van den Bossche
AU  - Wolfgang Waltenberger
AU  - Claudia Wulz
AU  - Tahys Janssen
AU  - Daniel Ocampo Henao
AU  - Thomas van Laer
AU  - Pierre van Mechelen
AU  - Donya Ahmadi
AU  - Jas Bierkens
AU  - Nordin Breugelmans
AU  - Soumya Dansana
AU  - Alexandre de Moor
AU  - Martin Delcourt
AU  - Stef Duponcheel
AU  - Chirayu Gupta
AU  - Felix Johannes Heyen
AU  - Yanwen Hong
AU  - Kai Kang
AU  - Pavlo Kashko
AU  - Steven Lowette
AU  - Inna Makarenko
AU  - Saranya Nandakumar
AU  - Jeremi Niedziela
AU  - Stefaan Tavernier
AU  - Michael Tytgat
AU  - Gerrit van Onsem
AU  - Senne van Putte
AU  - Tiepolo Wybouw
AU  - Aya Beshr
AU  - Bugra Bilin
AU  - Franco Caviglia Roman
AU  - Barbara Clerbaux
AU  - Aloke Kumar Das
AU  - Isabelle de Bruyn
AU  - Gilles de Lentdecker
AU  - Eliott Ducarme
AU  - Hugues Evard
AU  - Laurent Favart
AU  - Ilia Kalaitzidou
PY  - 2026
DA  - 2026/09/03
PB  - HAL
DO  - 10.48550/arxiv.2609.04376
UR  - https://hal.science/hal-05759122v1
AB  - We report a measurement of the azimuthal asymmetry of muons from the decay of coherently photoproduced J/ψ mesons with respect to the second-order event plane in hadronic lead-lead (PbPb) collisions. The analysis is based on data collected by the CMS experiment at the LHC at a nucleon-nucleon center-of-mass energy of 5.36 TeV, corresponding to an integrated luminosity of 1.26 nb^−1. The asymmetry is quantified using the amplitude A_2 of the second-order harmonic modulation of the decay-muon azimuthal distribution. A negative A_2 = −0.194 ± 0.022 (stat.) ± 0.018 (syst.) is observed with a significance greater than five standard deviations for the first time. The A_2 values show no significant dependence on the J/ψ meson rapidity or the degree of overlap of the colliding ions. A theoretical model in which the coherently photoproduced J/ψ meson inherits the linear polarization of the incident photon is consistent with the data. When considered together with recent measurements of coherent ρ^0 → π^+π^- photoproduction in ultraperipheral collisions, these results provide a direct observation of spin dependence in the azimuthal asymmetry of decay products from coherently photoproduced vector mesons. In addition, the observed correlation with the event plane may enable a novel approach to reaction plane determination in the future.
ER  -