Exploring electroweak symmetry breaking in the scale-invariant Two-Higgs-Doublet Model

Sammanfattning: This thesis investigates the properties of a general scale-invariant Two-Higgs-Doublet Model and its phenomenological consequences with focus on the scalar sector. The concept suggests that introducing more CP-violation, both spontaneous and explicit, may make it possible to meet the Sakharov conditions and account for the Universe's baryon asymmetry. We define a modified renormalization scheme to preserve the mixings and masses of all the Higgs bosons, except for the physical Standard Model-like one, when going to effective theory. The latter is massless at tree-level, since the scale-invariant theory has a flat direction and only gets mass at one-loop level when the electroweak symmetry is broken. We conduct a parameter scan applying experimental and theoretical constraints, including oblique parameters, unitarity, positivity, and global minimum verification at one-loop. We discover multiple parameter points that satisfy these constraints in the effective theory. The oblique parameters constraint shows a preference for masses close to each other. In addition, the effective parameters removed the majority of valid tree-level parameters, with the positivity constraint being the most restrictive factor. When examining the parameter space, it becomes apparent that points with low tan(beta) values are generally preferred. Also, unitarity excludes regions of parameter space where the vacuum expectation value is purely imaginary.