We study for the first time the production of charmonia in nuclear ultraperipheral and electron-ion collisions based on a rigorous Green function formalism. Such formalism allows to incorporate properly formation effects (color transparency), as well as the quantum coherence inherent in higher-twist shadowing corrections related to the $|Q\overline{Q}⟩$ Fock component of the photon. The leading twist gluon shadowing associated with multigluon photon fluctuations is also included within the same formalism. The later effect represents the dominant source of shadowing at midrapidities in the LHC kinematic region, while the reduced effect of quark shadowing leads to a significant modification of differential cross sections $d\sigma /dy$ at forward and/or backwards rapidities. Model calculations for $d\sigma /dy$ are in a good agreement with available ultraperipheral nuclear $Pb\text{−}Pb$ collisions data on coherent charmonium production at RHIC and the LHC. In addition, we also perform predictions for nuclear effects in the electroproduction of charmonia, which can be verified by new data from electron-ion colliders.

中文翻译：

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重新审视核目标上查莫尼亚的相干光和电产生：绿函数形式主义


我们首次基于严格的格林函数形式研究了核超外周和电子-离子碰撞中查莫尼亚的产生。这种形式主义允许适当地结合形成效应（颜色透明度），以及与相关的高扭曲阴影校正中固有的量子相干性。 $|Q\overline{Q}⟩$ 光子的 Fock 分量。与多胶子光子涨落相关的主导扭曲胶子阴影也包含在相同的形式中。后者的影响代表了大型强子对撞机运动区域中速阴影的主要来源，而夸克阴影影响的减少导致微分横截面的显着修改 $d\sigma /dy$ 以向前和/或向后的速度。模型计算 $d\sigma /dy$ 与可用的超外围核有很好的一致性 $Pb\text{−}Pb$ RHIC 和 LHC 相干粲素产生的碰撞数据。此外，我们还对查莫尼亚电生产中的核效应进行了预测，这可以通过电子离子对撞机的新数据进行验证。