Scientific article
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Charged-particle multiplicities in pp interactions at √s=900 GeV measured with the ATLAS detector at the LHC

ContributorsATLAS Collaboration
Published inPhysics letters. B, vol. 688, no. 1, p. 21-42
Publication date2010

The first measurements from proton–proton collisions recorded with the ATLAS detector at the LHC are presented. Data were collected in December 2009 using a minimum-bias trigger during collisions at a centre-of-mass energy of 900 GeV. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity, and the relationship between mean transverse momentum and charged-particle multiplicity are measured for events with at least one charged particle in the kinematic range |η|<2.5|η|<2.5 and pT>500 MeV. The measurements are compared to Monte Carlo models of proton–proton collisions and to results from other experiments at the same centre-of-mass energy. The charged-particle multiplicity per event and unit of pseudorapidity at η=0 is measured to be 1.333±0.003(stat.)±0.040(syst.), which is 5–15% higher than the Monte Carlo models predict.

  • Charged-particle
  • Multiplicities
  • 900 GeV
  • LHC
  • Minimum bias
Citation (ISO format)
ATLAS Collaboration. Charged-particle multiplicities in <em>pp</em> interactions at √s=900 GeV measured with the ATLAS detector at the LHC. In: Physics letters. B, 2010, vol. 688, n° 1, p. 21–42. doi: 10.1016/j.physletb.2010.03.064
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Article (Published version)
ISSN of the journal0370-2693

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