Top quark physics and search for physics beyond the Standard Model at the Large Hadron Collider
IDPASC Portugal - PHD Programme 2019
2019 / 2020
Experimental Particle Physics
Instituto Superior Técnico
Laboratório de Instrumentação e Física Experimental de Partículas
Top quarks are primarily produced in pairs at a hadron collider. In the framework of the Standard Model (SM), each top quark decays into a W and a b quark. The top quark pair events can be characterized by the decays of the two W bosons. Top quarks are abundantly produced in proton-proton collisions at the LHC, and constitute the main background to searches for New Physics. A good understanding of the top quark events will allow a more sensitive reach into the realm of searches for BSM processes. The work will focus on studying the properties of the top quark dilepton final state and measure the tau and heavy flavour contents of top quark events. Studies of final states including 3rd generation leptons and quarks, such as tau leptons and b-jets, produced in association with top quark pair events may provide hint on New Physics processes and shed light on the anomalies of Lepton Flavor Universality measurements. The link between tau leptons and b-quark content to top events, and the possibly large content of heavy flavour in BSM final states will be used to further characterize the data, with the goal of discriminating between SM and BSM processes. An anomalous heavy flavor production is directly “visible” in this study. Deviations from SM predictions will indicate evidence for New Physics.