Thesis defense of Tim Christopher Brune

In this thesis, we explore two hypothetical extensions of the Standard Model of particle physics. First, we discuss implications of the Majoron model for neutrino mass generation with regard to the appearance of cosmic domain walls before performing an in-depth study of leptogenesis in a Majoron model that is extended by an additional right-handed SU(2)L triplet. We find that successful leptogenesis in this scenario is in principle possible and that the results partially apply also to the generic Majoron model. Second, we disuss an extension of the Standard Model containing vector-like leptons and new scalars as a solution to the discrepancy between the observed and predicted anomalous magnetic moment of the muon. We find that the model permits contributions to the anomalous magnetic moment that are compatible with experimental data, while simultaneously being in agreement with other experimental bounds on the model parameters.