Family symmetries and radiative corrections in multi-scalar extensions of the Standard Model

Research output: ThesisDoctoral Thesis (compilation)


The four articles contained in this thesis all concern aspects of model building beyond the Standard Model (BSM). While Paper I mainly serves as a ``tool paper'' in which the results can be used to simplify certain calculations of one-loop effects from new heavy particles, Paper II--IV all deal with consequences of family symmetries in several BSM scenarios.

Paper I. We derive expressions for any number of derivatives of the Coleman-Weinberg potential in a general renormalisable four-dimensional field theory with arbitrary number of fields with spin~$\leq$~1. These correspond to the one-loop contributions to scalar $n$-point functions neglecting external momenta. The results are applied to two singlet extensions of the Standard Model, where we study the one-loop effects on the triple-Higgs coupling from the new exotic heavy states.

Paper II. In this paper we study a non-supersymmetric trinification theory where a novel $\mathrm{SU}(3)_F$ family symmetry is imposed on the model. The tree-level scalar potential often has a global minimum where the trinification gauge group is broken to a Left-Right symmetric gauge group, and after integrating out all particles with masses of the order of the grand unification scale we show that the renormalisation group is able to trigger a radiative breaking down to the Standard Model gauge group with light Higgs doublets still remaining in the spectrum.

Paper III. This paper is about a supersymmetrised version of the $\mathrm{SU}(3)_F$ symmetric trinification model of Paper II. The absence of an appropriate scalar potential minimum is rectified by adding novel gauge adjoint chiral superfields. The resulting superpotential allows for a breaking of the grand unification symmetry, while all subsequent symmetry breaking scales are given by soft supersymmetry breaking parameters. The tree-level mass spectrum resulting from this soft breaking of supersymmetry is discussed.

Paper IV. A three Higgs doublet model is introduced with a $\mathrm{U}(1) \times \mathrm{U}(1)$  family symmetry that simultaneously enforces a Cabibbo quark mixing under charged current interactions and forbids tree-level flavour changing neutral currents. Furthermore, a hierarchy in the vacuum expectation values of the three doublets produces a SM-like Higgs boson and hierarchical fermion masses, and also causes the exotic scalar states to couple most strongly to the second quark family. A search strategy for the lightest charged scalar boson in the model is proposed that utilises the $c \bar{s}$ fusion channel, and is shown to be capable of probing a large portion of the model's parameter space. This is formulated in a model independent manner such that it can be directly applied to any model with the same discovery channel.


  • Jonas Wessén
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Subatomic Physics


  • Beyond the Standard Model, Trinification, Grand Unification, Three Higgs doublet models, Coleman-Weinberg potential, Supersymmetry, Left-Right symmetry, Fysicumarkivet A:2018:Wessén
Original languageEnglish
Awarding Institution
Supervisors/Assistant supervisor
Award date2018 May 18
Place of PublicationLund
  • Lund University, Faculty of Science, Department of Astronomy and Theoretical Physics
Print ISBNs978-91-7753-671-0
Electronic ISBNs978-91-7753-671-7
Publication statusPublished - 2018
Publication categoryResearch

Bibliographic note

Defence details Date: 2018-05-18 Time: 13:00 Place: Hall K404, Department of Physics, Sölvegatan 14A, Lund External reviewer(s) Name: Porod, Werner Title: Prof. Dr. Affiliation: Theoretische Physik II, Universität Würzburg, Germany ---

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Related research output

Camargo-Molina, J. E., Mandal, T., Roman Pasechnik & Wessén, J., 2018 Mar 1, In : Journal of High Energy Physics. 2018, 3, 24.

Research output: Contribution to journalArticle

Camargo-Molina, J. E., Morais, A. P., Astrid Ordell, Roman Pasechnik, Sampaio, M. O. P. & Wessén, J., 2017 Apr 1, In : Physical Review D - Particles, Fields, Gravitation and Cosmology. 95, 7, 075031.

Research output: Contribution to journalArticle

Camargo-Molina, J. E., Morais, A. P., Roman Pasechnik & Wessén, J., 2016 Sep 1, In : Journal of High Energy Physics. 2016, 9, 129.

Research output: Contribution to journalArticle

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