Karapınar, GülerDemir, Durmuş AliDemir, Durmuş AliKarapınar, Güler04.05. Department of Pyhsics01. Izmir Institute of Technology04. Faculty of Science2017-02-272017-02-272011Chatrchyan, S, Khachatryan, V., Sirunyan, A.M., Tumasyan, A., Adam, W., Bergauer, T., Dragicevic, M.,...CMS Collaboration (2011). Measurement of the underlying event activity at the LHC with √s = 7 TeV and comparison with √s = 0:9 TeV. Journal of High Energy Physics, 2011. doi:10.1007/JHEP09(2011)1091029-84791029-8479http://doi.org/10.1007/JHEP09(2011)109http://hdl.handle.net/11147/4915A measurement of the underlying activity in events with a jet of transverse momentum in the several GeV region is performed in proton-proton collisions at √ s = 0:9 and 7TeV, using data collected by the CMS experiment at the LHC. The production of charged particles with pseudorapidity |η|<2 and transverse momentum pT >0:5 GeV/c is studied in the azimuthal region transverse to that of the leading set of charged particles forming a track-jet. A significant growth of the average multiplicity and scalar-pT sum of the particles in the transverse region is observed with increasing pT of the leading trackjet, followed by a much slower rise above a few GeV/c. For track-jet pT larger than a few GeV/c, the activity in the transverse region is approximately doubled with a centreof- mass energy increase from 0:9 to 7TeV. Predictions of several QCD-inspired models as implemented in pythia are compared to the data.eninfo:eu-repo/semantics/openAccessHadron-hadron scatteringCompact Muon SolenoidLarge Hadron Collider (LHC)CMS detectorsHigh energy physicsArticle2-s2.0-8486328206510.1007/JHEP09(2011)109Top10%