Diffractive dijet photoproduction in ultraperipheral collisions at the LHC in next-to-leading order QCD

We make predictions for the cross sections of diffractive dijet photoproduction in pp, pA and AA ultraperipheral collisions (UPCs) at the LHC during Runs 1 and 2 using next-to-leading perturbative QCD. We find that the resulting cross sections are sufficiently large and, compared to lepton-proton scattering at HERA, have an enhanced sensitivity to small observed momentum fractions in the diffractive exchange, commonly denoted z_ℙ^jets, and an unprecedented reach in the invariant mass of the photon-nucleon system W. We examine two competing schemes of diffractive QCD factorization breaking, which assume either a global suppression factor or a suppression for resolved photons only and demonstrate that the two scenarios can be distinguished by the nuclear dependence of the distributions in the observed parton momentum fraction in the photon x_γ^jets.