Measurement of the total cross section from elastic scattering in pp collisions at √s=7TeV with the ATLAS detector

Abstract

© 2014 The Authors.A measurement of the total pp cross section at the LHC at √s=7TeV is presented. In a special run with high-β{star operator}beam optics, an integrated luminosity of 80 μb-1was accumulated in order to measure the differential elastic cross section as a function of the Mandelstam momentum transfer variable t. The measurement is performed with the ALFA sub-detector of ATLAS. Using a fit to the differential elastic cross section in the |t| range from 0.01GeV2to 0.1GeV2to extrapolate to |t|→0, the total cross section, σtot(pp→X), is measured via the optical theorem to be:σtot(pp→X)=95.35±0.38(stat.)±1.25(exp.)±0.37(extr.)mb, where the first error is statistical, the second accounts for all experimental systematic uncertainties and the last is related to uncertainties in the extrapolation to |t|→0. In addition, the slope of the elastic cross section at small |t| is determined to be B=19.73±0.14(stat.)±0.26(syst.)GeV-2.