Technische Universitat¨Mu¨nchenPhysik-DepartmentInstitut fur Theoretische Physik T30¨Univ.-Prof. Dr. Michael RatzBaryogenesis, Neutrino Masses,andDynamical Dark EnergyMarc-Thomas EiseleVollsta¨ndiger Abdruck der von der Fakulta¨t fu¨r Physik der Technischen Univer-sitat Munchen zur Erlangung des akademischen Grades eines¨ ¨Doktors der Naturwissenschaften (Dr. rer. nat.)genehmigten Dissertation.Vorsitzender: Univ.-Prof. Dr. Franz von FeilitzschPrufer der Dissertation: 1. Univ.-Prof. Dr. Michael Ratz¨2. Univ.-Prof. Dr. Andrzej Jerzy BurasDie Dissertation wurde am 11. September 2007 bei der Technischen Universit¨atMunchen eingereicht und durch die Fakultat fur Physik am 9. Oktober 2007¨ ¨ ¨angenommen.Abstract:Thisthesisconsidersseveralmodelsthatconnectdifferentareasofparticlephysicsand cosmology. Our first discussion in this context concerns a baryogenesis sce-nario, in which the baryon asymmetry of our universe is created through thedynamics of a dark energy field, thereby illustrating that these two topics mightberelated. Subsequently, several neutrinomassmodelsareanalyzed, whichmakeuse of an extra-dimensional setting to overcome certain problems of their four-dimensional counterparts. The central discussion of this thesis concerns a lep-togenesis model with many standard model singlets.