Broken symmetries and signatures

Andrew Liam Fitzpatrick

We consider three possible extensions of the Standard Model. In the first model, we explore the possibility to solve the strong CP problem and flavor puzzle in a model with fermions in the bulk of a warped extra dimensions, making use of the enhanced spacetime symmetries present in extra dimensions. In the second, we systematically explore the possible low-energy spectrum arising from gauge-mediated supersymmetry breaking when the messenger sector obeys a U (1) R-symmetry and all allowed renormalizable operators in the messenger sector are included. In the third, we study single-field models of inflation using an effective theory for the pions of spontaneously broken time translation invariance and explicitly prove a consistency relation for the three-point function of density perturbations.