Photonuclear interactions dominate the interaction rate at large impact
parameters of the colliding heavy ions via ultra-peripheral collisions
(UPC). These processes allow us to study an evolution of the gluon
content of protons and nuclei in new kinematic regime at the LHC.
The study of J/psi production allows for perturbative QCD considerations
which address the gluon saturation and nuclear shadowing. Results on J/psi
photoproduction cross sections both at forward and midrapidities are presented.
The measurements are compared with available models for better understanding
of QCD in this shadowing regime.
The light-meson photonuclear production in UPC at the LHC
approaches the black-disk limit of QCD. The cross sections of the
\rho^0 coherent photoproduction in Pb--Pb and Xe--Xe UPC were
measured for different nuclear-breakup classes. The results are
compared with model predictions.