Thesis

Search for the charged Higgs boson in proton-proton collisions at the LHC

• Call:

  IDPASC Portugal - PHD Programme 2017

• Academic Year:

  2017 / 2018

• Domain:

  Experimental Particle Physics

• Supervisor:

  Joao Varela

• Co-Supervisor:

  Michele Gallinaro

• Institution:

  Instituto Superior Técnico

• Host Institution:

  Laboratório de Instrumentação e Física Experimental de Partículas

• Abstract:

  The minimal supersymmetric extension of the standard model (MSSM) requires the introduction of two Higgs doublets in order to preserve supersymmetry. This leads to the prediction of five elementary Higgs particles: two CP-even (h, H), one CP-odd (A), and two charged (H±) states. The lower limit on the charged Higgs boson mass is approximately 80 GeV as determined by LEP experiments. The study aims at the search for a charged Higgs bosons, where the Higgs boson mass is either lighter or heavier than the top quark mass. If the mass of the charged Higgs boson is smaller than the difference between the masses of the top and the bottom quarks, the top quark can decay via t ? H+b. In the case of a “heavy” charged Higgs boson, the leading order QCD process gb?tH± gives a sizable production cross section at the LHC. The charged Higgs boson either decays through its dominant decay mode, H± ? t ?b, or through its leading sub dominant decay mode, H± ??±??, which accounts for a branching fraction of ?10% for tan ?(>5-10). 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 over the current limits with the additional data, and with improved analysis techniques.