Charged particle multiplicities in pp interactions at √s = 0.9, 2.36, and 7TeV


Khachatryan V., Sirunyan A., Tumasyan A., Adam W., Bergauer T., Dragicevic M., ...More

Journal of High Energy Physics, vol.2011, no.1, 2011 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 2011 Issue: 1
  • Publication Date: 2011
  • Doi Number: 10.1007/jhep01(2011)079
  • Journal Name: Journal of High Energy Physics
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Keywords: Hadron-hadron scattering
  • Yıldız Technical University Affiliated: No

Abstract

Measurements of primary charged hadron multiplicity distributions are presented for non-single-diffractive events in proton-proton collisions at centre-of-mass energies of √s = 0.9, 2.36, and 7TeV, in five pseudorapidity ranges from |η| < 0.5 to |η| < 2.4. The data were collected with the minimum-bias trigger of the CMS experiment during the LHC commissioning runs in 2009 and the 7TeV run in 2010. The multiplicity distribution at √s = 0.9 TeV is in agreement with previous measurements. At higher energies the increase of the mean multiplicity with √s is underestimated by most event generators. The average transverse momentum as a function of the multiplicity is also presented. The measurement of higher-order moments of the multiplicity distribution confirms the violation of Koba-Nielsen-Olesen scaling that has been observed at lower energies.