Proton opacity in the light of LHC diffractive data

We show that collider data on elastic pp (and p (p) over bar) scattering, including the LHC TOTEM data at 7 TeV, can be well described by a 3-channel eikonal model with only one Pomeron, with parameters that are naturally linked to the perturbative QCD (BFKL) framework. The proton opacity, determined in this way, is then used to account for sizeable absorptive effects. We study the recent measurements of ds/d Delta eta made by the ATLAS collaboration, where they select events with large rapidity gaps Delta eta. We demonstrate that the absorptive corrections noticeably change both the value and the Delta eta dependence of the cross section. We find that our parameter-free calculation is in agreement with these ATLAS data.