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Thesis

#### Alternative electroweak symmetry beaking based on conformal extensions of the standard model

##### Fulltext (public)

Thesis_Pascal_Humbert.pdf

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##### Supplementary Material (public)

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##### Citation

Humbert, P. (2016). Alternative electroweak symmetry beaking based on conformal extensions of the standard model. PhD Thesis, Ruprecht-Karls-Universität, Heidelberg.

Cite as: http://hdl.handle.net/11858/00-001M-0000-002B-863B-0

##### Abstract

In order to address the hierarchy problem and to simultaneously explain small neutrino masses, we study conformal extensions of the Standard Model (SM), which realize an inverse seesaw mechanism. Furthermore, we give a systematic discussion of the neutrino mass matrix in a generalized type-I seesaw set-up. We study the conformal inverse seesaw mechanism (CISS), in which the conformal symmetry is spontaneously broken via the Coleman-Weinberg mechanism at a few TeV. We confirm that in this set-up the electroweak vacuum expectation value and the Higgs mass are obtained within experimental uncertainties. The scalar sector in the broken phase contains, besides the Higgs, a massive scalar with a mass in the TeV-range and the pseudo-Goldstone boson of broken scale invariance with a mass of the order of hundreds of GeV. The CISS also features a hidden Abelian gauge symmetry. We show that the CISS generates active neutrino masses and mixings in agreement with oscillation data. Additionally, the neutrino spectrum contains a warm dark matter (DM) candidate with mass in the keV-range and tiny mixing of the order of 10