The project addresses the still unanswered question how electroweak symmetry is broken. The symmetry breaking mechanism of the standard model with one Higgs boson diers from models like the minimal supersymmetric standard model and models with large extra dimensions. To clarify how electroweak symmetry is broken is the goal of this research project. Models which are free of the problems of the standard model should be studied and developed. Next the phenomenological consequences of these models should be worked out for both direct searches for new particles and for avour physics. The \Large Hadron Collider" can produce particles which are responsible for electroweak symmetry breaking in the coming years. Additionally new avour physics experiments will be able to test the properties of these new particles. The theoretical work done in this project should facilitate the discrimination of dierent electroweak symmetry breaking models using the expected experimental progress.