The Underlying Event in Proton-Proton Collisions

In this thesis, studies of the underlying event in proton-proton colli√sions at a center-of-mass energy of s = 10 TeV are presented. Crucialingredient to underlying event models are multiple parton-parton scatters in single proton-proton collisions. The feasibility of measuring theunderlying event was investigated with the Compact Muon Solenoid(CMS) detector at the Large Hadron Collider (LHC) using chargedparticles and charged-particle jets.Systematic uncertainties of the underlying event measurement dueto detector misalignment and imperfect track reconstruction are foundto be negligible after Ldt = 1 pb−1 of data are available. Differentmodel predictions are compared with each other using fully simulatedMonte Carlo samples. It is found, that distinct models differ stronglyenough to tell them apart with early data.