Evidence for an energy-invariant “edge” in proton-proton scattering at very high energies

Accurate fits to pp and ¯ pp cross section data up to Tevatron energies, incorporating the constraints imposed by analyticity and unitarity, successfully predict the results of recent LHC and cosmic ray measurements, and suggest that the cross sections approach a black disc limit asymptotically. The approach to the limit is, however, very slow. We present a