The Underlying Event in Proton-Proton Collisions

Florian Bechtel
May 2009

Thesis Type:

In this thesis, studies of the underlying event in proton-proton collisions at a center-of-mass energy of √s = 10 TeV are presented. Crucial ingredient to underlying event models are multiple parton-parton scatters in single proton-proton collisions. The feasibility of measuring the underlying event was investigated with the Compact Muon Solenoid (CMS) detector at the Large Hadron Collider (LHC) using charged particles and charged-particle jets.

Systematic uncertainties of the underlying event measurement due to detector misalignment and imperfect track reconstruction are found to be negligible after ∫ L dt = 1 pb-1 of data are available. Different model predictions are compared with each other using fully simulated Monte Carlo samples. It is found, that distinct models differ strongly enough to tell them apart with early data.

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