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Extending the Standard Model with Confining and Conformal Dynamics

Posted on:2013-03-10Degree:Ph.DType:Dissertation
University:University of California, DavisCandidate:McRaven, John EmoryFull Text:PDF
GTID:1458390008978962Subject:Physics
Abstract/Summary:
This dissertation will provide a survey of models that involve extending the standard model with confining and conformal dynamics. We will study a series of models, describe them in detail, outline their phenomenology, and provide some search strategies for finding them.;The Gaugephobic Higgs model provides an interpolation between three different models of electroweak symmetry breaking: Higgsless models, Randall-Sundrum models, and the Standard Model. At parameter points between the extremes, Standard Model Higgs signals are present at reduced rates, and Higgsless Kaluza-Klein excitations are present with shifted masses and couplings, as well as signals from exotic quarks necessary to protect the Zbb coupling. Using a new implementation of the model in SHERPA, we show the LHC signals which differentiate the generic Gaugephobic Higgs model from its limiting cases. These are all signals involving a Higgs coupling to a Kaluza-Klein gauge boson or quark. We identify the clean signal pp → W (i) → WH mediated by a Kaluza-Klein W, which can be present at large rates and is enhanced for even Kaluza-Klein numbers. Due to the very hard lepton coming from the W+/- decay, this signature has little background, and provides a better discovery channel for the Higgs than any of the Standard Model modes, over its entire mass range. A Higgs radiated from new heavy quarks also has large rates, but is much less promising due to very high multiplicity final states.;The AdS/CFT conjectures a relation between Extra Dimensional models in AdS5 space, such as the Gaugephobic Higgs Model, and 4D Conformal Field theories. The notion of conformality has found its way into several phenomenological models for TeV-scale physics extending the standard model. We proceed to explore the phenomenology of a new heavy quark that transforms under a hidden strongly coupled conformal gauge group in addition to transforming under QCD. This object would form states similar to R-Hadrons. The heavy state would leave very little of its energy in the calorimeter, so while detecting the presence of a heavy stable state would be easy, measuring the strength of the detecting it would require accurate measurements of missing energy, or the ability to identify it in the muon tracker.;We then study the phenomenology of a 4D model of electroweak symmetry breaking through the condensation of magnetic monopoles. A new generation of fermions with magnetic charges in addition to electric charges is introduced. The dyons condense and break the electroweak symmetry. The magnetic coupling is inversely proportional to the electric coupling, causing it to be strong. The processes involving magnetic couplings thus provide interesting phenomenology to study. We primarily study the processes involving di-photon production and compare it to early LHC results.;Finally, we calculate triangle anomalies for fermions with non-canonical scaling dimensions. The most well known example of such fermions (aka unfermions) occurs in Seiberg duality where the matching of anomalies (including mesinos with scaling dimensions between 3/2 and 5/2) is a crucial test of duality. By weakly gauging the non-local action for an unfermion, we calculate the one-loop three-current amplitude. Despite the fact that there are more graphs with more complicated propagators and vertices, we find that the calculation can be completed in a way that nearly parallels the usual case. We show that the anomaly factor for fermionic unparticles is independent of the scaling dimension and identical to that for ordinary fermions. This can be viewed as a confirmation that unparticle actions correctly capture the physics of conformal fixed point theories like Banks-Zaks or SUSY QCD.
Keywords/Search Tags:Extending the standard model, Conformal
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