Volume 101, Number 2, February 2013
|Number of page(s)||5|
|Published online||05 February 2013|
Luminosity-independent measurements of total, elastic and inelastic cross-sections 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, Deptartment of Physics - Cleveland, OH, USA
10 Penn State University, Department of Physics - University Park, PA, USA
Received: 5 December 2012
Accepted: 3 January 2013
The TOTEM experiment at the LHC has performed the first luminosity-independent determination of the total proton-proton cross-section at . 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* = 90 m) 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 σel = (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 possible: |ρ| = 0.145 ± 0.091.
PACS: 13.60.Hb – Total and inclusive cross sections (including deep-inelastic processes)
© CERN for the benefit of the TOTEM Collaboration
Copyright © EPLA, 2013 Copyright CERN for the benefit of the TOTEM Collaboration. Published by the EPLA under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.