Thesis

Machine Learning and Measurements of the Higgs boson properties

• Call:

  PT-CERN call 2020/1

• Academic Year:

  2020/2021

• 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:

  The subject of this thesis is the search for double Higgs production, decaying into taus and b-jets, at the Large Hadron Collider (LHC). The thesis is placed in the context of the Portuguese participation in the CMS experiment at the LHC, and it is linked to the Beyond the Standard Model (BSM) searches in the more general context of the searches for New Physics processes at the LHC. In the course of the last forty years, the SM has received increasing and consistent verification by precise experimental tests of its predictions, culminating in 2012 with the discovery of a new particle, which appears to be “the” Higgs boson. There are, however, compelling reasons to believe the SM is not complete. In particular, the LIP/CMS group is engaged in the study of SM and BSM processes to fully exploit the opportunities of the unparalleled energy of the LHC collisions. A large amount of data of approximately 150/fb have been collected in Run1+Run2 and are available to study this process. With the upcoming Run3, additional 300/fb of data may become available in the next few years and there will be excellent opportunities for major discoveries in this domain. The work plan includes the study of the double Higgs production, each subsequently decaying to pairs of taus and b-jets. Advanced Machine Learning (ML) techniques will be used in the separation of signal and background events. The candidate is expected to work in a team with a group of researchers. Searches for new physics in this channel can be significantly improved with the additional data, and with improved analysis techniques. The research will be carried out in the context of the Portuguese participation in the CMS experiment at the LHC, in the framework of the activities of one of the outstanding research groups in High-Energy Physics in Portugal. Citing the Report of the recent Institutional Evaluation performed by an international review panel nominated by FCT: “The LIP-CMS group, while small in size, is really outstanding and world-class”.