Abstract

The TOTEM experiment at the LHC has performed the first luminosity-independent determination of the total proton-proton cross-section at root s = 7 TeV. This technique is based on the optical theorem and requires simultaneous measurements of the inelastic rate - accomplished with the forward charged-particle telescopes T1 and T2 in the range 3.1 < vertical bar eta vertical bar < 6.5 - and of the elastic rate by detecting the outcoming protons with Roman Pot detectors. The data presented here were collected in a dedicated run in 2011 with special beam optics (beta* = 90m) and Roman Pots approaching the beam close enough to register elastic events with squared four-momentum transfers vertical bar t vertical bar as low as 5 . 10(-3) GeV2. The luminosity-independent results for the elastic, inelastic and total cross-sections are sigma(el) = (25.1 +/- 1.1) mb, sigma(inel) = (72.9 +/- 1.5) mb and sigma(tot) = (98.0 +/- 2.5) mb, respectively. At the same time this method yields the integrated luminosity, in agreement with measurements by CMS. TOTEM has also determined the total cross-section in two complementary ways, both using the CMS luminosity measurement as an input. The first method sums the elastic and inelastic cross-sections and thus does not depend on the rho parameter. The second applies the optical theorem to the elastic-scattering measurements only and therefore is free of the T1 and T2 measurement uncertainties. The methods, having very different systematic dependences, give results in excellent agreement. Moreover, the rho-independent measurement makes a first estimate for the rho parameter at root s = 7 TeV possible: vertical bar rho vertical bar = 0.145 +/- 0.091.

Autore Pugliese

• Berardi Vincenzo

Tutti gli autori

• Antchev G , Aspell P , Atanassov I , Avati V , Baechler J , Berardi V , Berretti M , Bossini E , Bozzo M , Brogi P , Brucken E , Buzzo A , Cafagna F S , Calicchio M , Catanesi M G , Covault C , Csanad M , Csoergo T , Deile M , Doubek M , Eggert K , Eremin V , Ferretti R , Ferro F , Fiergolski A , Garcia F , Giani S , Greco V , Grzanka L , Heino J , Hilden T , Intonti R A , Kaspar J , Kopal J , Kundrat V , Kurvinen K , Lami S , Latino G , Lauhakangas R , Leszko T , Lippma E , Lokajicek M , Lo Vetere M , Rodriguez F Lucas , Macri M , Maki T , Mercadante A , Minafra N , Minutoli S , Nemes F , Niewiadomski H , Oliveri E , Oljemark F , Orava R , Oriunno M , Osterberg K , Palazzi P , Prochazka J , Quinto M , Radermacher E , Radicioni E , Ravotti F , Robutti E , Ropelewski L , Ruggiero G , Saarikko H , Santroni A , Scribano A , Smajek J , Snoeys W , Sziklai J , Taylor C , Turini N , Vacek V , Vitek M , Welti J , Whitmore J , Wyszkowski P

Titolo volume/Rivista

EUROPHYSICS LETTERS

Anno di pubblicazione

2013

ISSN

0295-5075

ISBN

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