Contributions from ultraperipheral collisions to the forward rapidity gap distribution in pPb collisions at the CERN Large Hadron Collider at sNN =8.16 TeV

In this Letter, we consider strong and electromagnetic (ultraperipheral) mechanisms in proton-nucleus coherent diffraction at the CERN Large Hadron Collider. We explicitly demonstrate the dominance of the latter and explain the CMS data on the forward rapidity gap distribution in pPb collisions at sNN=8.16 TeV. In particular, we provide simple estimates, which give a good, semiquantitative description of both magnitude and shape of the ΔηF distribution in the Pomeron-proton topology. We also make predictions for the proton-oxygen run.