Woude, S. van der (2017) Radiative Symmetry Breaking in minimal Conformally Invariant extensions of the Standard Model. Master's Thesis / Essay, Physics.

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Abstract
The Standard Model is expected to be only an effective theory because, for one, the Standard Model does not describe gravity. Additionally the Standard Model can not describe Dark Matter and faces the Hierarchy Problem. Beyond the Standard Model (BSM) theories are devised to solve these and other problems of the Standard Model. However, these BSM theories face some strict limitations from experiments because up to now not a single particle physics experiment has measured any significant deviations from the Standard Model. In this thesis a class of BSM theories called the minimal conformally symmetric SM extensions are discussed. These theories are promising BSM candidates because the conformal symmetry results in a theory which does not suffer from the Hierarchy Problem. The minimality ensures that the theory will closely resemble the Standard Model and thus not have a too big effect on experimental data. Because conformally symmetric theories do not exhibit classical spontaneous symmetry breaking another mechanism for spontaneous symmetry breaking is necessary. Therefore a large part of this work is spent on explaining Radiative Symmetry Breaking, which describes spontaneous symmetry breaking due to quantum corrections. The concept of Radiative Symmetry Breaking was first introduced by S. Coleman and E. Weinberg. Some minimal conformal extensions of the Standard Model are discussed, one of which is the extension of the Standard Model with one scalar. The phenomenology but also the possible problems of these extensions are discussed to determine which extensions are good candidates to be a BSM theory. It will be argued that already a two scalar extension is able to provide a theory which is reliable up to the Planck Scale. The idea of Asymptotic Safety is briefly discussed to introduce the reader to another possible way in which the Standard Model can be extended.
Item Type:  Thesis (Master's Thesis / Essay) 

Degree programme:  Physics 
Thesis type:  Master's Thesis / Essay 
Language:  English 
Date Deposited:  15 Feb 2018 08:30 
Last Modified:  15 Feb 2018 08:30 
URI:  http://fse.studenttheses.ub.rug.nl/id/eprint/15555 
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