Thesis

Top quark physics and search for physics beyond the Standard Model at the Large Hadron Collider

• Call:

  PT-CERN Call 2022/1

• Academic Year:

  2022

• Domain:

  Astroparticle Physics

• Supervisor:

  Michele Gallinaro

• Co-Supervisor:

  Joao Varela

• Institution:

  Instituto Superior Técnico (Universidade de Lisboa)

• Host Institution:

  Laboratório de Instrumentação e Física Experimental de Partículas

• Abstract:

  Motivated by the deviations observed in rare semi-leptonic decays of B mesons, the subject of the thesis is the study of lepton flavour universality (LFU) in top quark events produced in proton-proton collisions at the LHC. The LFU measurement is performed in the leptonic decays of W bosons in top quark events, including electrons, muons and taus. Measurements in this channel can be significantly improved by using advanced Machine learning techniques in the separation of signal and background events and by exploiting the large amount of data: the ones currently available, approximately 150/fb from Run1+Run2, will be reinforced by the upcoming Run3, providing additional 300/fb. The thesis, placed in the context of the Portuguese participation in the CMS experiment at the LHC, is integrated in the activities of the “Top quark” working group, and it is strongly linked to the Beyond the Standard Model searches within the CMS experiment.