Energy dependence of exclusive J/ photoproduction off protons in ultra-peripheral p-Pb collisions at sNN=5.02 TeV $$mathrm J/psi $$ J / ψ photoproduction off protons in ultra-peripheral p–Pb collisions at $$sqrts_mathrm scriptscriptstyle NN = 5.02$$ s NN = 5.02 TeV

The ALICE Collaboration has measured the energy dependence of exclusive photoproduction of J/ vector mesons off proton targets in ultra-peripheral p-Pb collisions at a centre-of-mass energy per nucleon pair =5.02 TeV. The e+e- and +- decay channels are used to measure the cross section as a function of the rapidity of the J/ in the range -2.5<2.7, corresponding to an energy in the p centre-of-mass in the interval 40<550 GeV. The measurements, which are consistent with a power law dependence of the exclusive J/ photoproduction cross section, are compared to previous results from HERA and the LHC and to several theoretical models. They are found to be compatible with previous measurements.