Seminarium "Teoria cząstek elementarnych i kosmologia"

In this talk, based on our recent work (Phys. Rev. D 110 (2024) 7, 075029, [2406.16050]), we explore theoretical constraints on models in which the Standard Model field content is extended by vector-like fermions and, in some cases, a real scalar singlet. Our approach focuses on the requirements of electroweak vacuum stability, perturbativity of model couplings, and gauge coupling unification, utilizing renormalization group equations. We show that a careful analysis of these factors leads to stringent constraints on the parameter space of the considered models. This, in turn, has significant implications for phenomenology, as we illustrate through examples of the double Higgs boson production, electroweak precision observables, and the electroweak phase transition.