Potentiel d'observation de la technicouleur à l'aide de l'expérience ATLAS

The Standard Model of particle physics describes interactions among particles. In this picture, the Higgs mechanism is responsible for the mass description of the theory. The outcome of the symmetry breaking is the appearance of the higgs boson as a physical state. This particle associated with the mass mechanism is believed to be an important key leading to the understanding of high energy physics. Nevertheless, this model is not the end of the story. Many theoretical and phenomenological arguments lead physicists to believe that this description is not complete. The constraints on the Higgs sector are becoming stronger and model builders are wondering if an alternative approach would not be the solution. Many theories beyond the Standard Model has appeared to solve the problem of the Standard Model. Among them are the weIl known supersymmetry and technicolor models. Technicolor and other similar constructions referred to as strong symmetry models, replace the Higgs by a composite particle whose constituent fermions are described by a strong interaction. The phenomenology of these models is essentially defined by the new bound states allowed by this strong interaction. Nowadays, these models are gaining in popularity and promise sorne striking signatures at LHC. Recent progress has been made in the field and new models are now available. Among the signatures of technicolor, the vector techni-mesons are very promising. Here, we analyse two channels in this sector, in the context of the strawman model, whose combination allows us to extract a parameter of the theory. This study follows from our work at Les Houches, where we have shown, using fast simulation, that these channels are accessible at LHC. This new study is based on ATLAS full detector simulation and enables us to extract the allowed parameter space for an integrated luminosity of 10 fb-l. Some backgrounds were partially simulated with fast simulation due to their large cross sections. A detailed comparison of fast and full simulation has been done in order to perform the analysis with better statistics. Finally, an alternative model will be discussed and its phenomenology for the vector and Higgs sector will be described.