The TOTEM experiment at the LHC has performed the first luminosity-independent determination of the total proton-proton cross-section at √ s = 7TeV. 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 < |η| < 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 (β* = 90m) and Roman Pots approaching the beam close enough to register elastic events with squared four-momentum transfers |t| as low as 5 · 10-3 GeV2. The luminosity-independent results for the elastic, inelastic and total cross-sections are σ el = (25.1 ±1.1)mb, σinel = (72.9 ±1.5)mb and σtot = (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 ρ 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 ρ -independent measurement makes a first estimate for the ρ parameter at √ s = 7TeV possible: |ρ| = 0.145 ±0.091.
Luminosity-independent measurements of total, elastic and inelastic cross-sections at √s = 7 TeV / 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.; Csorgo 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.; Lippmaa E.; Lokajicek M.; Lo Vetere M.; Lucas Rodriguez F.; 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.. - In: EUROPHYSICS LETTERS. - ISSN 0295-5075. - ELETTRONICO. - 101:(2013), pp. 0-0. [10.1209/0295-5075/101/21004]
Luminosity-independent measurements of total, elastic and inelastic cross-sections at √s = 7 TeV
Latino G.Membro del Collaboration Group
;
2013
Abstract
The TOTEM experiment at the LHC has performed the first luminosity-independent determination of the total proton-proton cross-section at √ s = 7TeV. 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 < |η| < 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 (β* = 90m) and Roman Pots approaching the beam close enough to register elastic events with squared four-momentum transfers |t| as low as 5 · 10-3 GeV2. The luminosity-independent results for the elastic, inelastic and total cross-sections are σ el = (25.1 ±1.1)mb, σinel = (72.9 ±1.5)mb and σtot = (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 ρ 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 ρ -independent measurement makes a first estimate for the ρ parameter at √ s = 7TeV possible: |ρ| = 0.145 ±0.091.
I documenti in FLORE sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
