Measurement of proton-proton elastic scattering and total cross-section at

^1a Institute of Physics of the Academy of Sciences of the Czech Republic - Praha, Czech Republic, EU
^1b Czech Technical University - Praha, Czech Republic, EU
² National Institute of Chemical Physics and Biophysics NICPB - Tallinn, Estonia, EU
^3a Helsinki Institute of Physics - Helsinki, Finland, EU
^3b Department of Physics, University of Helsinki - Helsinki, Finland, EU
⁴ MTA Wigner Research Center, RMKI - Budapest, Hungary, EU
^5a INFN Sezione di Bari - Bari, Italy, EU
^5b Dipartimento Interateneo di Fisica di Bari - Bari, Italy, EU
^6a Sezione INFN di Genova - Genova, Italy, EU
^6b Università degli Studi di Genova - Genova, Italy, EU
^7a INFN Sezione di Pisa - Pisa, Italy, EU
^7b Università degli Studi di Siena and Gruppo Collegato INFN di Siena - Siena, Italy, EU
⁸ CERN - Geneva, Switzerland
⁹ Case Western Reserve University, Department of Physics - Cleveland, OH, USA
¹⁰ Penn State University, Department of Physics - University Park, PA, USA

Received: 5 December 2012
Accepted: 3 January 2013

Abstract

At the LHC energy of , under various beam and background conditions, luminosities, and Roman Pot positions, TOTEM has measured the differential cross-section for proton-proton elastic scattering as a function of the four-momentum transfer squared t. The results of the different analyses are in excellent agreement demonstrating no sizeable dependence on the beam conditions. Due to the very close approach of the Roman Pot detectors to the beam center (≈5σ_beam) in a dedicated run with β* = 90 m, |t|-values down to 5·10⁻³ GeV² were reached. The exponential slope of the differential elastic cross-section in this newly explored |t|-region remained unchanged and thus an exponential fit with only one constant B = (19.9 ± 0.3) GeV⁻² over the large |t|-range from 0.005 to 0.2 GeV² describes the differential distribution well. The high precision of the measurement and the large fit range lead to an error on the slope parameter B which is remarkably small compared to previous experiments. It allows a precise extrapolation over the non-visible cross-section (only 9%) to t = 0. With the luminosity from CMS, the elastic cross-section was determined to be (25.4 ± 1.1) mb, and using in addition the optical theorem, the total pp cross-section was derived to be (98.6 ± 2.2) mb. For model comparisons the t-distributions are tabulated including the large |t|-range of the previous measurement (TOTEM Collaboration (Antchev G. et al), EPL, 95 (2011) 41001).