Studies of Top Quark Decay Kinematics

Hannah Nelson

My research focuses on the kinematics of top quark decays, specifically how momentum could affect tracking of particles produced in these decays.

The Standard Model is the theory that describes the fundamental particles and forces that govern our universe. The Higgs Boson is an elementary particle that is an excitation of the Higgs Field, which gives particles mass. Quarks are elementary particles that combine with others to make composite particles. The top quark is the heaviest quark. If the Higgs boson is made of undiscovered constituent particles, it is likely that the top quark is also made of similar particles based on how strongly they interact. In this case, events with four top quarks would be produced in excess of predictions from current theories. The purpose of this project is to study top quark kinematics to determine how to distinguish between background and signal top decays. A simulation (MADGRAPH) was used to generate events where t and decay to a bottom quark and a W boson, and the W bosons decay to qq¯. Analysis shows that as the top quark’s transverse momentum increases, the distance between the top quark and its decays decreases. This decrease demonstrates that the two high momentum tops in a four top process can be analyzed primarily by using position.