Scientific article
Open access

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

ContributorsATLAS Collaboration
Published inNew journal of physics, vol. 13, no. 053033, 68
Publication date2011

Measurements are presented from proton–proton collisions at centre-of-mass energies of √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 pT>100 MeV, is measured to be 3.483±0.009 (stat)±0.106 (syst) at √s=0.9 TeV and 5.630±0.003 (stat)±0.169 (syst) at √s=7 TeV.

  • Inclusive production with identified hadrons
  • Perturbative calculations
Citation (ISO format)
ATLAS Collaboration. Charged-particle multiplicities in <em>pp</em> interactions measured with the ATLAS detector at the LHC. In: New journal of physics, 2011, vol. 13, n° 053033, p. 68. doi: 10.1088/1367-2630/13/5/053033
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Article (Published version)
ISSN of the journal1367-2630

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