Abstract
Ultraperipheral collisions (UPCs) of ultra-relativistic ions give an opportunity to study photon-nucleus interactions at high energies and, hence, obtain new information of nuclear parton distributions (nPDFs) at small \(x\). In particular, we discuss coherent \({J \mathord{\left/ {\vphantom {J \psi }} \right. \kern-0em} \psi }\) photoproduction on nuclei in Pb–Pb UPCs and the resulting new constraints on gluon nuclear shadowing. We also report on our calculations of the cross section of dijet photoproduction in Pb–Pb UPCs in the LHC kinematics using the framework of collinear next-to-leading order (NLO) perturbative QCD. Our results favorably compare to the preliminary data and illustrate its sensitivity to nuclear modifications of nPDFs in a wide range of the momentum fraction \(x\).
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Funding
The reported study was funded by RFBR according to the research project no. 17-52-12070 NNIO_a.
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Guzey, V. Dijet Photoproduction in Ultraperipheral Collisions at the LHC and Nuclear PDFs at Small x. Phys. Part. Nuclei Lett. 16, 498–502 (2019). https://doi.org/10.1134/S1547477119050133
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DOI: https://doi.org/10.1134/S1547477119050133