Search for heavy vector-like quarks with the ATLAS experiment at the LHC collider
FCT / IDPASC call 2012
Experimental Particle Physics
Laboratório de Instrumentação e Física Experimental de Partículas
Different Standard Model extensions, such as extra-dimensional models with custodial symmetry, as well as little Higgs models, predict the existence of an enlarged gauge sector with the top quark playing a special role. In these models one or more top partners are introduced with different charges, depending on the SU(2)L representation and on the hypercharge. These quarks are expected to couple mainly to the third SM generation, originating characteristic dilepton and trilepton final states. The LHC proton-proton collision data collected by the ATLAS experiment at CERN will allow to probe these models, constraining the allowed parameter space, and eventually to discover and establish the identity of these new particles. For this, a detailed analysis of the different signals and backgrounds, as well as a good understanding of the experimental and theoretical sources of uncertainty, will be required.