Aad, G.; Abbott, B.; Abdallah, J.; Abdel Khalek, S.; Abdinov, O.; Aben, R.; Abi, B.; Abolins, M.; AbouZeid, O. S.; Abramowicz, H.; Abreu, H.; Abreu, R.; Abulaiti, Y.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Adelman, J.; Adomeit, Stefanie; Adye, T.; Agatonovic-Jovin, T.; Aguilar-Saavedra, J. A.; Agustoni, M.; Ahlen, S. P.; Ahmadov, F.; Aielli, G.; Akerstedt, H.; Akesson, T. P. A. (2014): Measurement of the total cross section from elastic scattering in pp. In: Nuclear Physics B, Vol. 889: S. 486-548
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### Abstract

A measurement of the total pp cross section at the LHC at root s = 7 TeV is presented. In a special run with high-beta* beam optics, an integrated luminosity of 80 mu b(-1) was 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 vertical bar t vertical bar range from 0.01 GeV2 to 0.1 GeV2 to extrapolate to vertical bar t vertical bar —\textgreater 0, the total cross section, sigma(tot)(pp —\textgreater 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|t|→0. In addition, the slope of the elastic cross section at small |t||t| is determined to be View the MathML sourceB=19.73±0.14(stat.)±0.26(syst.) GeV−2.