Date Awarded

Fall 2016

Document Type

Dissertation

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Physics

Advisor

Christopher D Carone

Committee Member

Joshua Erlich

Committee Member

Marc Sher

Committee Member

Patricia Vahle

Committee Member

José Goity

Abstract

Through beyond standard model formulations we are able to suggest solutions to some of the current shortcomings of the standard model. In this thesis we focus in particular on inflation, the hierarchy of fermion masses, scale invariant extensions and dark matter candidates. First we present a model of hybrid natural inflation based on the discrete group S_3, the smallest non-Abelian group. The S_3 potential has an accidental symmetry whose breaking results in a pseudo-Goldstone boson with the appropriate potential for a slow-rolling inflaton. The hybrid adjective comes from the fact that inflation is ended by additional scalar fields interacting with the inflaton. At some point during inflation, this interaction forces the additional scalars to develop vacuum expectation values, then they fall to a global minimum and inflation ends. We continue with another inflation model, in this case involving a two-field potential. This potential comes from the breaking of a flavor symmetry, the one that yields the hierarchy of fermion masses. Depending on the choice of parameters, the path followed by the inflaton may or not reach a point where inflation ends by a hybrid mechanism. For every model presented we study the field content and the parameters to demonstrate that there are solutions that follow the constraints from current experimental observations. Then we move to classically scale invariant extensions of the standard model. We proceed with a model where one-loop corrections break a non-Abelian gauge symmetry in a dark sector. This breaking provides an origin for the electroweak scale and gives mass to the gauge multiplet. For some parameter regions this massive gauge boson is a dark matter candidate. To finish, we also develop a model where we employ strong interactions in the dark sector. The particular dynamics of this model set the electroweak scale and generate a massive pseudo-Goldstone boson appropriate for dark matter.

DOI

http://doi.org/10.21220/S2H013

Rights

© The Author

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