Tese de Doutorado #273: Adriano Cherchiglia

In this thesis we present a general view on regularization ambiguities and develop a systematization on how such ambiguities can be related to momentum routing invariance of Feynman diagrams and symmetries. We apply our formalism to a variety of theories and examples such as: the Higgs boson decay to two photons, the two photon scattering, induction (or not) of a Chern-Simons tem on gravitational effective models, supersymmetric electrodynamics and the anomaly puzzle. We also study the role played by quadratic divergences on a variety of examples showing its connection (or not) to the ambiguities aforementioned.