Gauge Anomalies and Neutrino Seesaw Models

Despite the success of the Standard Model concerning theoretical predictions, there are several experimental results that cannot be explained and there are reasons to believe that there exists new physics beyond it. Neutrino oscillations, and hence their masses, are examples of this. Experimentally it is known that neutrinos masses are quite small, when compared to all Standard Model particle masses. Among the theoretical possibilities to explain these tiny masses, the seesaw mechanism is a simple and well-motivated framework. In its minimal version, heavy particles are introduced that decouple from the theory in the early universe. To build consistent theories, classical symmetries need to be preserved at quantum level, so that there are no anomalies. The cancellation of these anomalies leads to constraints in the parameters of the theory. One attractive solution is to realize the anomaly cancellation through the modication of the gauge symmetry. In this thesis we present a short review of some features of the Standard Model, relevant to the aspects mentioned above. We then discuss the implementation of new anomaly free gauge symmetries and their connection with the avour structure of the neutrino mass matrix obtained through the seesaw mechanism. The possibility of distinguishing dierent gauge symmetries and seesaw realizations at collider experiments is also addressed.