Multiplicity Dependence of Two-Particle Angular Correlations in Proton-Proton Collisions Measured with ALICE at the LHC

The thesis presents measurements of particle pair yields per trigger particle obtained from two-particle azimuthal correlations in proton-proton collisions at $\sqrt{s}=$ 0.9, 2.76, and 7.0 TeV recorded with the ALICE (A Large Ion Collider Experiment) detector at the LHC (Large Hadron Collider). The yields are studied as a function of the charged particle multiplicity. The analysis results provide information about low-$p_{\mathrm{T}}$ parton fragmentation and the contribution of multiple parton interactions to particle production. The ALICE data are compared to Pythia6, Pythia8, and Phojet simulations. Based on the analysis results, theoretical models can be optimized for LHC energies.