How precisely will the total cross section be measured at the Large Hadron Collider?

It is very likely that hadronic scattering will enter a new regime at the CERN Large Hadron Collider, as the black-disk limit is reached. This will lead to a severe change in the t dependence of the real part and of the slope of the elastic scattering amplitude, and in turn, this may bias the measurement of the total cross section. We examine this issue and suggest new strategies to test the reliability of the total cross-section measurements.

Benchmarks for the forward observables at RHIC, the Tevatron-run II, and the LHC.

We present predictions on the total cross sections and on the rho parameter for present and future pp and (-)pp colliders, and on total cross sections for gammap-->hadrons at cosmic-ray energies and for gammagamma-->hadrons up to sqrt[s]=1 TeV. These predictions are based on an extensive study of possible analytic parametrizations invoking the largest hadronic dataset available at t=0. The uncertainties on total cross sections reach 1.9% at the Relativistic Heavy Ion Collider, 3.1% at the Tevatron, and 4.8% at the Large Hadron Collider, whereas those on the rho parameter are, respectively, 5.4%, 5.2%, and 5.4%.