Measurement of elastic pp scattering at  TeV in the Coulomb–nuclear interference region: determination of the -parameter and the total cross-section

G. Antchev; P. Aspell; I. Atanassov; V. Avati; J. Baechler; V. Berardi; M. Berretti; E. Bossini; U. Bottigli; M. Bozzo; P. Broulím; H. Burkhardt; A. Buzzo; F. S. Cafagna; C. E. Campanella; M. G. Catanesi; M. Csanád; T. Csörgő; M. Deile; F. De Leonardis; A. D’Orazio; M. Doubek; K. Eggert; V. Eremin; F. Ferro; A. Fiergolski; F. Garcia; V. Georgiev; S. Giani; L. Grzanka; C. Guaragnella; J. Hammerbauer; J. Heino; A. Karev; J. Kašpar; J. Kopal; V. Kundrát; S. Lami; G. Latino; R. Lauhakangas; R. Linhart; E. Lippmaa; J. Lippmaa; M. V. Lokajíček; L. Losurdo; M. Lo Vetere; F. Lucas Rodríguez; M. Macrí; A. Mercadante; N. Minafra; S. Minutoli; T. Naaranoja; F. Nemes; H. Niewiadomski; E. Oliveri; F. Oljemark; R. Orava; M. Oriunno; K. Österberg; P. Palazzi; L. Paločko; V. Passaro; Z. Peroutka; V. Petruzzelli; T. Politi; J. Procházka; F. Prudenzano; M. Quinto; E. Radermacher; E. Radicioni; F. Ravotti; S. Redaelli; E. Robutti; L. Ropelewski; G. Ruggiero; H. Saarikko; B. Salvachua; A. Scribano; J. Smajek; W. Snoeys; J. Sziklai; C. Taylor; N. Turini; V. Vacek; G. Valentino; J. Welti; J. Wenninger; P. Wyszkowski; K. Zielinski

doi:10.1140/epjc/s10052-016-4399-8

2024 Impact factor 4.8

Particles and Fields

Open Access

Eur. Phys. J. C (2016) 76: 661
https://doi.org/10.1140/epjc/s10052-016-4399-8

Regular Article - Experimental Physics

Measurement of elastic pp scattering at $\sqrt{\hbox {s}} = \hbox {8}$ TeV in the Coulomb–nuclear interference region: determination of the $\mathbf {\rho }$ -parameter and the total cross-section

G. Antchev¹, P. Aspell¹⁷, I. Atanassov¹, V. Avati¹⁶^,17, J. Baechler¹⁷, V. Berardi⁹^,10, M. Berretti¹⁵^,17, E. Bossini¹⁵, U. Bottigli¹⁵, M. Bozzo¹²^,13, P. Broulím¹, H. Burkhardt¹⁷, A. Buzzo¹², F. S. Cafagna⁹, C. E. Campanella⁹^,11, M. G. Catanesi⁹, M. Csanád⁷, T. Csörgő⁷^,8, M. Deile¹¹, F. De Leonardis⁹^,11, A. D’Orazio⁹^,11, M. Doubek³, K. Eggert¹⁸, V. Eremin¹, F. Ferro¹², A. Fiergolski⁹, F. Garcia⁵, V. Georgiev¹, S. Giani¹⁷, L. Grzanka¹⁶, C. Guaragnella⁹^,11, J. Hammerbauer¹, J. Heino⁵, A. Karev¹⁷, J. Kašpar²^,17^*, J. Kopal², V. Kundrát², S. Lami¹⁴, G. Latino¹⁵, R. Lauhakangas⁵, R. Linhart¹, E. Lippmaa⁴, J. Lippmaa⁴, M. V. Lokajíček², L. Losurdo¹⁵, M. Lo Vetere¹²^,13, F. Lucas Rodríguez¹⁷, M. Macrí¹², A. Mercadante⁹, N. Minafra¹⁰^,17, S. Minutoli¹², T. Naaranoja⁵^,6, F. Nemes⁷, H. Niewiadomski¹⁸, E. Oliveri¹⁷, F. Oljemark⁵^,6, R. Orava⁵^,6, M. Oriunno¹, K. Österberg⁵^,6, P. Palazzi¹⁷, L. Paločko¹, V. Passaro⁹^,11, Z. Peroutka¹, V. Petruzzelli⁹^,11, T. Politi⁹^,11, J. Procházka², F. Prudenzano⁹^,11, M. Quinto⁹^,10, E. Radermacher¹⁷, E. Radicioni⁹, F. Ravotti¹⁷, S. Redaelli¹⁷, E. Robutti¹², L. Ropelewski¹⁷, G. Ruggiero¹⁷, H. Saarikko⁵^,6, B. Salvachua¹⁷, A. Scribano¹⁴, J. Smajek¹⁷, W. Snoeys¹⁷, J. Sziklai⁷, C. Taylor¹⁸, N. Turini¹⁵, V. Vacek³, G. Valentino¹⁷, J. Welti⁵^,6, J. Wenninger¹⁷, P. Wyszkowski¹⁶ and K. Zielinski¹⁶

¹ University of West Bohemia, Pilsen, Czech Republic
² Institute of Physics of the Academy of Sciences of the Czech Republic, Prague, Czech Republic
³ Czech Technical University, Prague, Czech Republic
⁴ National Institute of Chemical Physics and Biophysics NICPB, Tallinn, Estonia
⁵ Helsinki Institute of Physics, Helsinki, Finland
⁶ Department of Physics, University of Helsinki, Helsinki, Finland
⁷ Wigner Research Centre for Physics, RMKI, Budapest, Hungary
⁸ KRF University College, Gyöngyös, Hungary
⁹ INFN Sezione di Bari, Bari, Italy
¹⁰ Dipartimento Interateneo di Fisica di Bari, Bari, Italy
¹¹ Dipartimento di Ingegneria Elettrica e dell’Informazione - Politecnico di Bari, Bari, Italy
¹² INFN Sezione di Genova, Genoa, Italy
¹³ Università degli Studi di Genova, Genoa, Italy
¹⁴ INFN Sezione di Pisa, Pisa, Italy
¹⁵ Università degli Studi di Siena and Gruppo Collegato INFN di Siena, Siena, Italy
¹⁶ AGH University of Science and Technology, Krakow, Poland
¹⁷ CERN, Geneva, Switzerland
¹⁸ Department of Physics, Case Western Reserve University, Cleveland, OH, USA

^* e-mail: jan.kaspar@cern.ch

Received: 12 July 2016
Accepted: 26 September 2016
Published online: 30 November 2016

Abstract

The TOTEM experiment at the CERN LHC has measured elastic proton–proton scattering at the centre-of-mass energy $\sqrt{s}=8\,$ TeV and four-momentum transfers squared, |t|, from $6\times 10^{-4}$ to 0.2 GeV $^{2}$ . Near the lower end of the t-interval the differential cross-section is sensitive to the interference between the hadronic and the electromagnetic scattering amplitudes. This article presents the elastic cross-section measurement and the constraints it imposes on the functional forms of the modulus and phase of the hadronic elastic amplitude. The data exclude the traditional Simplified West and Yennie interference formula that requires a constant phase and a purely exponential modulus of the hadronic amplitude. For parametrisations of the hadronic modulus with second- or third-order polynomials in the exponent, the data are compatible with hadronic phase functions giving either central or peripheral behaviour in the impact parameter picture of elastic scattering. In both cases, the $\rho$ -parameter is found to be $0.12 \pm 0.03$ . The results for the total hadronic cross-section are $\sigma _\mathrm{tot} = (102.9 \pm 2.3)$ mb and $(103.0 \pm 2.3)$ mb for central and peripheral phase formulations, respectively. Both are consistent with previous TOTEM measurements.