EXTRACTING THREE PROPERTIES OF THE TOP QUARK FROM ANGULAR DISTRIBUTIONS

Abstract

The top quark is the most recently-discovered fundamental matter constituent particle in the Standard Model of particle physics. Experimentally describing its properties helps constrain theoretical models seeking to provide solutions to open problems in particle physics. This thesis describes how the linearized parton-level forward-backward asymmetry (AFB) and the anomalous chromoelectric (d) and chromomagnetic (mu) moments of the top quark have been measured using proton-proton collisions at a center-of-mass energy of 13 TeV, produced at the CERN LHC and collected by the CMS detector, corresponding to an integrated luminosity of 35.9 fb^{-1}. Candidate top quark/antiquark pair events decaying to a muon or electron and jets in final states with low and high Lorentz boosts are selected and reconstructed using a kinematic fit to the decay products expected for top quark/antiquark pair final states. Parameters of interest are extracted from independent binned-likelihood fits to the observed data based on beyond the Standard Model extensions to the leading-order cross sections for top quark/antiquark pair production from quark-antiquark and gluon-gluon initial states. The values found for the parameters are AFB=0.048^{+0.095}_{-0.087}(stat.)^{+0.020}_{-0.029}(syst.), mu=-0.024^{+0.013}_{-0.009}(stat.)^{+0.016}_{-0.011}(syst.), and a limit on the magnitude of |d|<0.03 at 95\% confidence level.