Vector meson photoproduction in ultra-peripheral p-Pb collisions measured using the ALICE detector

The strong electromagnetic fields generated by ultra-relativistic heavy ions offer the possibil- ity to study gamma-gamma, gamma-nucleus and gamma-proton processes at the LHC in ultra- peripheral Pb-Pb and p-Pb collisions (UPC). As exclusive photoproduction of vector mesons is sensitive to the gluon distribution of the interacting target it allows one to study saturation and shadowing phenomena. Here we report on the ALICE measurement of vector meson photoproduction in p-Pb UPC at p s NN = 5.02 TeV. In these asymmetric collisions, the photon is most likely coming from the Pb nucleus. As a result, the center-of-mass energy of the photon-proton system is constrained by the rapidity of the vector meson which is measured in the laboratory frame with respect to the proton beam direction. We present the results on vector meson photoproduction in several intervals of the photon-proton center-of-mass energy