Proton-proton elastic scattering at the LHC energy of

^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 KFKI 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, Deptartment of Physics - Cleveland, OH, USA
¹⁰ Penn State University, Department of Physics - University Park, PA, USA
¹¹ INRNE-BAS, Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences - Sofia, Bulgaria, EU.
¹² Department of Atomic Physics, ELTE University - Budapest, Hungary, EU.
¹³ Ioffe Physical-Technical Institute of Russian Academy of Sciences - St Petersburg, Russian Federation.
¹⁴ Warsaw University of Technology - Warsaw, Poland, EU.
¹⁵ Institute of Nuclear Physics, Polish Academy of Sciences - Cracow, Poland, EU.
¹⁶ KRF - Gyöngyös, Hungary, EU.
¹⁷ SLAC National Accelerator Laboratory - Stanford, CA, USA.

Received: 27 June 2011
Accepted: 4 July 2011

Abstract

Proton-proton elastic scattering has been measured by the TOTEM experiment at the CERN Large Hadron Collider at in dedicated runs with the Roman Pot detectors placed as close as seven times the transverse beam size (σ_beam) from the outgoing beams. After careful study of the accelerator optics and the detector alignment, |t|, the square of four-momentum transferred in the elastic scattering process, has been determined with an uncertainty of . In this letter, first results of the differential cross-section are presented covering a |t|-range from 0.36 to 2.5 GeV². The differential cross-section in the range 0.36<|t|<0.47 GeV² is described by an exponential with a slope parameter B=(23.6±0.5^stat±0.4^syst) GeV⁻², followed by a significant diffractive minimum at |t|=(0.53±0.01^stat±0.01^syst) GeV². For |t|-values larger than ∼1.5 GeV², the cross-section exhibits a power law behaviour with an exponent of −7.8±0.3^stat±0.1^syst. When compared to predictions based on the different available models, the data show a strong discriminative power despite the small t-range covered.