First measurement of the total proton-proton cross-section at the LHC energy of √s = 7 TeV

Abstract

TOTEMhas measured the differential cross-section for elastic proton-proton scattering at the LHC energy of √s = 7TeV analysing data from a short run with dedicated large-β* optics. A single exponential fit with a slope B = (20.1±0.2stat ±0.3syst)GeV-2 describes the range of the four-momentum transfer squared |t| from 0.02 to 0.33 GeV2. After the extrapolation to |t| = 0, a total elastic scattering cross-section of (24.8 ± 0.2stat ± 1.2 syst)mb was obtained. Applying the optical theorem and using the luminosity measurement from CMS, a total proton-proton cross-section of (98.3 ± 0.2stat ± 2.8syst)mb was deduced which is in good agreement with the expectation from the overall fit of previously measured data over a large range of center-of-mass energies. From the total and elastic pp cross-section measurements, an inelastic pp cross-section of (73.5 ± 0.6stat+1.8-1.3syst)mb was inferred.