First measurement of the underlying event activity at the LHC with √ = 0.9 TeV


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

European Physical Journal C, vol.70, no.3, pp.555-572, 2010 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 70 Issue: 3
  • Publication Date: 2010
  • Doi Number: 10.1140/epjc/s10052-010-1453-9
  • Journal Name: European Physical Journal C
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.555-572
  • Yıldız Technical University Affiliated: No

Abstract

A measurement of the underlying activity in scattering processes with pT scale in the GeV region is performed in proton-proton collisions at √ = 0.9 TeV, using data collected by the CMS experiment at the LHC. Charged particle production is studied with reference to the direction of a leading object, either a charged particle or a set of charged particles forming a jet. Predictions of several QCD-inspired models as implemented in PYTHIA are compared, after full detector simulation, to the data. The models generally predict too little production of charged particles with pseudorapidity {pipe}η{pipe} < 2, pT > 0.5 GeV/c, and azimuthal direction transverse to that of the leading object. © 2010 CERN for benefit of the CMS collaboration.