High scale boundary conditions in extensions of the standard model

McDowall, John (2019) High scale boundary conditions in extensions of the standard model. PhD thesis, University of Glasgow.

Abstract

The recent discovery of the Higgs boson by the ATLAS and CMS exper- iments and the subsequent measurements of it properties are the latest vindications of the Standard Model of particle physics. The SM has a number of well known flaws, and the continuing dearth of Beyond the Standard Model signatures from experiment has led to investigations into whether the SM is valid up to very high scales. The motivation for much of this work comes from the quartic Higgs coupling λ and its β function, which run to an extremely small values at high scales. These may be hints of new UV dynamics, in particular the Multiple Point Principle which posits the existence of a second degenerate minimum in the effective potential at the Planck scale, and Asymptotic Safety, where the dimensionless couplings of the potential run towards an interacting UV fixed point. In this work we will investi- gate the possibility for similar high scale boundary conditions in extensions of the Standard Model. Specifically, we look at the Real Singlet model, the Complex Sin- glet model, the Type-II Two Higgs Doublet Model, and the Inert Doublet Model. We will apply the relevant theoretical constraints to the parameter space of theses models, as well as experimental constraints such as those from ATLAS, CMS, LEP, the Tevatron, WMAP, Planck and LUX. Points that pass these constraints will also be investigated for their validity under a number of high scale boundary conditions on its scalar sector, and the valid parameter space will be checked for signatures in the mass spectrum that can be probed by current and future collider experiments.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Beyond the Standard Model Physics, particle physics phenomenol- ogy, Higgs physics, dark matter physics.
• Subjects: Q Science > QC Physics
• Colleges/Schools: College of Science and Engineering > School of Physics and Astronomy
• Funder's Name: Science & Technology Facilities Council (STFC)
• Supervisor's Name: Miller, Dr. David J.
• Date of Award: 2019
• Depositing User: Mr John McDowall
• Unique ID: glathesis:2019-41082
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 13 Mar 2019 08:31
• Last Modified: 05 Mar 2020 21:45
• Thesis DOI: 10.5525/gla.thesis.41082
• URI: https://theses.gla.ac.uk/id/eprint/41082