Results on ultra-peripheral interactions in Pb-Pb and p-Pb collisions in ALICE

Abstract: Ultra-relativistic heavy ions generate strong electromagnetic fields which offer the possibility to study $\gamma$-nucleus and $\gamma$-proton interactions at the LHC in the so called ultra-peripheral collisions (UPC). Here we report ALICE results on J/psi photoproduction measured in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV and in p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV.