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

TOTEM has measured the differential cross-section for elastic proton-proton scattering at the LHC energy of √s = 7TeV analyzing data from a short run with dedicated large Beta∗ optics. A single exponential fit with B = 20. 1GeV**−2 (all errors are given in the text) describes the lowest range of the squared four-momentum transfer |t| from 0. 02 to 0. 3GeV**2. After the extrapolation to |t| = 0, a total elastic scattering cross-section of 24. 8mb was obtained. Applying the Optical Theorem and using the luminosity measurement from CMS, a total proton-proton cross-section of 98. 3mb was deduced which is in good agreement with the expectation from the overall fit of previously measured data over a large range of energies. From the total and elastic pp cross-section measurements, an inelastic pp cross-section of (73: 5\0: 6stat +1: 8 -1: 3 syst) mb was inferred. PACS 13. 60. Hb: Total and inclusive cross sections