Dilepton azimuthal anisotropy from coherent J/ψ photoproduction in hadronic Pb-Pb collisions
Abstract
Hadron-based event-plane estimators can be affected by nonflow and autocorrelation biases, especially at low multiplicity. Coherent J/ψ photoproduction offers a complementary geometry reference through the correlation between quasireal-photon polarization and the reaction plane. We calculate the second-order dilepton coefficient A2 relative to the reaction plane in hadronic Pb--Pb collisions at √(sNN)=5.36 TeV within an equivalent-photon and generalized vector-meson-dominance Glauber framework. Nuclear diffraction and two-source interference produce a pronounced transverse-momentum dependence, while the rapidity dependence is weak. We also compare two treatments of coherent scattering in the overlap region of the two colliding nuclei. Suppressing the contribution from this region reduces the yield and strengthens the integrated polarization--reaction-plane correlation, with the largest differences in central and semicentral collisions and smaller differences toward peripheral collisions. Joint measurements of the coherent yield and A2 can constrain how hadronic interactions disrupt nuclear coherence and clarify the photoproduction mechanism. With sufficient tagged yields, azimuthal correlations involving decay leptons from photoproduced J/ψ mesons could complement studies of collectivity, with potential future applications to small systems.
Related
- Spin-dependent azimuthal asymmetry of coherent J/ψ photoproduction in hadronic PbPb collisions at √(sNN) = 5.36 TeV
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- Measurement of the Higgs boson decay to a low-mass dilepton system and a photon in pp collisions at √s = 13 and 13.6 TeV with the ATLAS detector
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BibTeX
@misc{hua2026dilepton,
title = {{Dilepton azimuthal anisotropy from coherent $J/ψ$ photoproduction in hadronic Pb-Pb collisions}},
author = {Xueli Hua and Xin Wu and Shuai Yang and Wangmei Zha},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.35149},
eprint = {2610.35149},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.35149},
note = {CC BY-NC-SA 4.0},
}
RIS
TY - UNPB
TI - Dilepton azimuthal anisotropy from coherent J/ψ photoproduction in hadronic Pb-Pb collisions
AU - Xueli Hua
AU - Xin Wu
AU - Shuai Yang
AU - Wangmei Zha
PY - 2026
DA - 2026/10/26
PB - arXiv
DO - 10.48550/arxiv.2610.35149
UR - https://arxiv.org/abs/2610.35149
AB - Hadron-based event-plane estimators can be affected by nonflow and autocorrelation biases, especially at low multiplicity. Coherent J/ψ photoproduction offers a complementary geometry reference through the correlation between quasireal-photon polarization and the reaction plane. We calculate the second-order dilepton coefficient A_2 relative to the reaction plane in hadronic Pb--Pb collisions at √(s_NN)=5.36 TeV within an equivalent-photon and generalized vector-meson-dominance Glauber framework. Nuclear diffraction and two-source interference produce a pronounced transverse-momentum dependence, while the rapidity dependence is weak. We also compare two treatments of coherent scattering in the overlap region of the two colliding nuclei. Suppressing the contribution from this region reduces the yield and strengthens the integrated polarization--reaction-plane correlation, with the largest differences in central and semicentral collisions and smaller differences toward peripheral collisions. Joint measurements of the coherent yield and A_2 can constrain how hadronic interactions disrupt nuclear coherence and clarify the photoproduction mechanism. With sufficient tagged yields, azimuthal correlations involving decay leptons from photoproduced J/ψ mesons could complement studies of collectivity, with potential future applications to small systems.
ER -