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Revisiting the role of saturation in diffractive vector meson production

Department of Physics, University of Jyväskylä, P.O. Box 35, 40014 University of Jyväskylä, Finland and Helsinki Institute of Physics, P.O. Box 64, 00014 University of Helsinki, Finland

Physics Department, Brookhaven National Laboratory, Upton, New York 11973, USA

Department of Physics and Astronomy, Wayne State University, Detroit, Michigan 48201, USA

Institute of Particle Physics and Key Laboratory of Quark and Lepton Physics (MOE), Central China Normal University, Wuhan, 430079, Hubei, China

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Phys. Rev. D 114, L031505 – Published 13 August, 2026

DOI: https://doi.org/10.1103/t8t7-5djl

Abstract

We perform a global Bayesian analysis of coherent and incoherent diffractive $J / ψ$ photoproduction in $γ + p$ and $γ + Pb$ collisions using a color glass condensate (CGC)-based framework and ultraperipheral collision data from the Large Hadron Collider (LHC), corrected for the expected effect of electromagnetic dissociation (EMD). Using Gaussian-process emulators of the underlying CGC calculations, we infer model parameters from a combined set of HERA and LHC measurements. We find that the $γ + Pb$ data with EMD correction substantially reduce the previously observed tension between proton and nuclear datasets, enabling a consistent simultaneous description of diffractive $J / ψ$ production in $γ + p$ and $γ + Pb$ collisions within the CGC framework.

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Phys. Rev. D 114, L031505– Published 13 August, 2026

Vol. 114, Iss. 3 — 1 August 2026

Received 24 June 2026
Accepted 28 July 2026

DOI: https://doi.org/10.1103/t8t7-5djl

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.

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Revisiting the role of saturation in diffractive vector meson production

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