Charged-particle multiplicities in pp interactions measured with the ATLAS detector at the LHC

Barton, Adam and Borissov, Guennadi and Bouhova-Thacker, Eva and Brodbeck, Timothy and Catmore, James and Cheatham, Sue and Chilingarov, Alexandre and Davidson, Ruth and de Mora, Lee and Fox, Harald and Henderson, Robert and Hughes, Gareth and Jones, Roger William Lewis and Kartvelishvili, Vakhtang and Long, Robin and Love, Peter and Ratoff, Peter and Sloan, Terence and Smizanska, Maria and Walder, James (2011) Charged-particle multiplicities in pp interactions measured with the ATLAS detector at the LHC. New Journal of Physics, 13 (5). ISSN 1367-2630

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Abstract

Measurements are presented from proton-proton collisions at centre-of-mass energies of root s = 0.9, 2.36 and 7 TeV recorded with the ATLAS detector at the LHC. Events were collected using a single-arm minimum-bias trigger. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity and the relationship between the mean transverse momentum and charged-particle multiplicity are measured. Measurements in different regions of phase space are shown, providing diffraction-reduced measurements as well as more inclusive ones. The observed distributions are corrected to well-defined phase-space regions, using model-independent corrections. The results are compared to each other and to various Monte Carlo (MC) models, including a new AMBT1 pythia6 tune. In all the kinematic regions considered, the particle multiplicities are higher than predicted by the MC models. The central charged-particle multiplicity per event and unit of pseudorapidity, for tracks with p(T) > 100 MeV, is measured to be 3.483 +/- 0.009 (stat) +/- 0.106 (syst) at root s = 0.9 TeV and 5.630 +/- 0.003 (stat) +/- 0.169 (syst) at root s = 7 TeV.

Item Type:
Journal Article
Journal or Publication Title:
New Journal of Physics
Additional Information:
© 2011 CERN for the benefit of the ATLAS Collaboration, published under licence by IOP Publishing Ltd for the Institute of Physics and Deutsche Physikalische Gesellschaft. Content may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation and DOI.
Uncontrolled Keywords:
/dk/atira/pure/researchoutput/libraryofcongress/qc
Subjects:
ID Code:
68058
Deposited By:
Deposited On:
13 Dec 2013 16:42
Refereed?:
Yes
Published?:
Published
Last Modified:
04 Jul 2020 02:09