アイテム詳細

要旨

In this thesis we study an ultraviolet (UV) complete extension of the Standard Model (SM) that aims to address the origin of the light neutrino masses, the gauge hierarchy problem, and the electroweak vacuum stability. It has been recently shown that the SM extended by right-handed neutrinos and without an explicit Higgs mass term can not only reproduce the expected light neutrino masses but also radiatively generate the Higgs mass. This scenario, dubbed as the “Neutrino Option”, has been UV completed within a minimal conformal extension obtained by further introducing two real scalar singlets. These models require new singlet neutrino masses of the order 10 − 500 PeV, which is far above the testable range at collider experiments. Moreover, the Higgs scalar potential in these scenarios is subject to a meta-stable/unstable phase at high energies. This work explores the possibility of modifying this minimal conformal framework such that the right-handed singlet neutrino mass scale is lowered to scales that can be tested in current/future experiments. To this extent, we set up the particle content and quantum numbers so that after the breaking of conformal symmetry `a la Coleman-Weinberg, an inverse seesaw framework is achieved instead of the type-I seesaw that characterizes the previous scenarios. Furthermore, we show that with the appropriate number of scalar degrees of freedom, the Higgs scalar potential can be rendered fully stable within our model.