Classical scale-invariance, the electroweak scale and vector dark matter

We consider a classically scale-invariant extension of the standard model in which a dark, non-Abelian gauge symmetry is spontaneously broken via the Coleman-Weinberg mechanism. Higgs portal couplings between the dark and standard model sectors provide an origin for the Higgs mass squared parameter and, hence, the electroweak scale. We find that choices for model parameters exist in which the dark gauge multiplet is viable as dark matter.Comment: 15 pages LaTeX, 3 figures. v2: references added, v3: minor revisions, more references adde

Predictions for the Dirac CP-Violating Phase from Sum Rules

We explore the implications of recent results relating the Dirac CP-violating phase to predicted and measured leptonic mixing angles within a standard set of theoretical scenarios in which charged lepton corrections are responsible for generating a non-zero value of the reactor mixing angle. We employ a full set of leptonic sum rules as required by the unitarity of the lepton mixing matrix, which can be reduced to predictions for the observable mixing angles and the Dirac CP-violating phase in terms of model parameters. These sum rules are investigated within a given set of theoretical scenarios for the neutrino sector diagonalization matrix for several known classes of charged lepton corrections. The results provide explicit maps of the allowed model parameter space within each given scenario and assumed form of charged lepton perturbations.Comment: 37 pages, 58 figures. V2: Typos corrected, references added, content matches version published in PR

Solving Problems of the Standard Model through Scale Invariance, Dark Matter, Inflation and Flavor Symmetry

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

Dark chiral symmetry breaking and the origin of the electroweak scale

We study a classically scale-invariant model in which strong dynamics in a dark sector sets the scale of electroweak symmetry breaking. Our model is distinct from others of this type that have appeared in the recent literature. We show that the Higgs sector of the model is phenomenologically viable and that the spectrum of dark sector states includes a partially composite dark matter candidate. (C) 2015 The Authors. Published by Elsevier B.V