Thesis

Search for the Higgs boson at ATLAS/LHC, in associated production with a Z boson

• Call:

  FCT / IDPASC call 2010

• Academic Year:

  2010 / 2011

• Domain:

  Experimental Particle Physics

• Supervisor:

  Agostinho Gomes

• Co-Supervisor:

  Amelia Maio

• Institution:

  Faculdade de Ciências - Universidade de Lisboa

• Host Institution:

  Laboratório de Instrumentação e Física Experimental de Partículas

• Abstract:

  One of the hot topics of the LHC is the search for the Higgs boson, that is responsible for the Electro-Weak (EW) symmetry breaking mechanism. The Standard Model (SM) of particle physics favors a light mass Higgs boson, close to the exclusion limit imposed at LEP. This mass regime is especially challenging, since the Higgs boson will decay predominantly to a b-bbar quark pair and there will be a large background from QCD jets with similar momenta. A recent publication demonstrates that the associated production of a Higgs with a W or Z boson, could be sufficient for a Higgs discovery in the low mass regime, proposing a new detection technique. The idea is to select the few cases where the Higgs is produced with very large transverse momentum, so the two b quarks hadronize to two b-jets that overlap each other and are reconstructed as a single fat jet. Careful studies of the jet substructure can be used to distinguish the Higgs decay products from the huge QCD background. The LIP-ATLAS group is involved in the searches for the Higgs boson in the low mass regime. This thesis project proposes to search for the Higgs boson in the associated production of a Higgs with a Z boson using this new technique. The candidate should have availability to travel to CERN in Geneva, Switzerland, since the project implies frequent stays at CERN, that might last for several months per year, to participate in the data taking, in collaboration meetings and to present results.