Skip to main content
eScholarship
Open Access Publications from the University of California

Scholarly Works (2 results)

  • Article
  • Peer Reviewed
UC Davis Previously Published Works (2010)
More than half a million minimum-bias events of LHC collision data were collected by the ATLAS experiment in December 2009 at centre-of-mass energies of 0.9 TeV and 2.36 TeV. This paper reports on studies of the initial performance of the ATLAS detector from these data. Comparisons between data and Monte Carlo predictions are shown for distributions of several track-and calorimeter-based quantities. The good performance of the ATLAS detector in these first data gives confidence for successful running at higher energies.
    Cover page: Performance of the ATLAS detector using first collision dataCreative Commons 'BY' version 4.0 license
    • Article
    • Peer Reviewed
    UC Davis Previously Published Works (2010)
    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 chargedparticle multiplicity are measured for events with at least one charged particle in the kinematic range |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.
      Cover page: Charged-particle multiplicities in pp interactions at s=900 GeV measured with the ATLAS detector at the LHCCreative Commons 'BY' version 4.0 license
      Top