Non-linear effects in coherent photoproduction of heavy quarkonia off nuclei: Green's function formalism vs Balitsky-Kovchegov equation
Abstract
We present an analysis of QCD non-linear (NL) effects in the coherent photoproduction of charmonia off nuclei at high energies corresponding to future measurements at the LHC. For the first time, we confront the energy evolution of such effects within our rigorous Green's function (GF) formalism with results from Refs.~\cite{Cepila:2025ujv,Cepila:2024qge}, which are based on the solution of the leading-order (LO) and next-to-leading-order (NLO) Balitsky-Kovchegov (BK) evolution equations. We demonstrate a huge difference in the NL effects between these two formalisms, exhibiting a rather strong rise with photon energy. Our analysis shows that NLO calculations of the BK equation from Ref.~\cite{Cepila:2024qge} slow down the rate of the high-energy LO evolution of NL effects. Although these calculations reduce the differences between the GF and BK predictions, they still lead to a much stronger onset of leading-twist shadowing effects compared to the GF formalism. The BK equation in its present form cannot be applied to nuclear targets and thus requires a non-trivial modification that properly incorporates quantum coherence effects.
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BibTeX
@misc{koval2026nonlinear,
title = {{Non-linear effects in coherent photoproduction of heavy quarkonia off nuclei: Green's function formalism vs Balitsky-Kovchegov equation}},
author = {I. Koval and J. Nemchik and J. Óbertová},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.36992},
eprint = {2610.36992},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.36992},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Non-linear effects in coherent photoproduction of heavy quarkonia off nuclei: Green's function formalism vs Balitsky-Kovchegov equation
AU - I. Koval
AU - J. Nemchik
AU - J. Óbertová
PY - 2026
DA - 2026/10/27
PB - arXiv
DO - 10.48550/arxiv.2610.36992
UR - https://arxiv.org/abs/2610.36992
AB - We present an analysis of QCD non-linear (NL) effects in the coherent photoproduction of charmonia off nuclei at high energies corresponding to future measurements at the LHC. For the first time, we confront the energy evolution of such effects within our rigorous Green's function (GF) formalism with results from Refs.~\cite{Cepila:2025ujv,Cepila:2024qge}, which are based on the solution of the leading-order (LO) and next-to-leading-order (NLO) Balitsky-Kovchegov (BK) evolution equations. We demonstrate a huge difference in the NL effects between these two formalisms, exhibiting a rather strong rise with photon energy. Our analysis shows that NLO calculations of the BK equation from Ref.~\cite{Cepila:2024qge} slow down the rate of the high-energy LO evolution of NL effects. Although these calculations reduce the differences between the GF and BK predictions, they still lead to a much stronger onset of leading-twist shadowing effects compared to the GF formalism. The BK equation in its present form cannot be applied to nuclear targets and thus requires a non-trivial modification that properly incorporates quantum coherence effects.
ER -