Abstract
A measurement of the underlying activity in scattering processes with p T scale in the GeV region is performed in proton–proton collisions at 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 |η|<2, p T >0.5 GeV/c, and azimuthal direction transverse to that of the leading object.
CMS Collaboration