| In this thesis we will study issues related to the stability of extra-dimensional models and discuss an important advance in Randall-Sundrum (RS) type models that has allowed them to remain phenomenologically viable. In particular, we will derive a fun damental six-dimensional action which leads to the stabilization of Arkani-Hamed, Dimopolous, Dvali (ADD) type models. This action extends the stabilization mechanism of Arkani-Hamed, Hall, Smith, and Weiner in the Poincare invariant vacuum to a generally covariant scenario. We will also derive a renormalization group flow for hidden brane scalar operators in the RS1 model that leads to a local effective field theory with a variable position for the hidden brane. This formalism simpifies calculations (e.g. the Goldberger-Wise stabilization mechanism) in the RS background. Finally, we will show how the promotion of the global custodial isospin symmetry in the Standard Model to an SU(2)R bulk gauge field rescues the "RS1 with bulk gauge fields" scenario from being ruled out by isospin violating operators. |
