Unification of families and forces meets the Standard Model
PT-CERN Call 2021/1
Universidade de Aveiro
CIDMA - Centro de Investigação em Matemática e Aplicações da Universidade de Aveiro
The tremendous phenomenological success of the Standard Model (SM) suggests that its flavour structure and gauge interactions may not be arbitrary but should have a fundamental first-principles explanation. In this thesis, the goal is to explore how the basic distinctive properties of the SM dynamically emerge from a recently proposed unified New Physics (NP) framework [1,2,3] tying together both flavour physics and Grand Unified Theory (GUT) concepts. This framework is suggested by the gauge Left-Right-Color-Family Grand Unification under the exceptional E8 symmetry, the unifying force. Among the most appealing emergent properties of this theory is the Higgs-matter unification with a highly-constrained massless chiral sector featuring a single universal gauge and Yukawa coupling at the GUT scale. Furthermore, as a result of the family symmetry, the proton lifetime can be large enough to allow for low-scale Grand Unification such that, if confirmed in this thesis, can potentially become a paradigm shifting opportunity. At the electroweak scale, the minimal SM-like effective field theory limit of this GUT is consistent with the observed large hierarchies in the quark mass spectra and mixing already at tree level. However, a complete calculation of the SM particle spectra and mixing is necessary to conclusively validate the model. On the NP side, the model can offer three generations of SU(2) doublet vector-like leptons and up to two singlet leptoquarks. With a rather limited freedom but, potentially, a remarkable predictive power, the goal of this thesis is to complete the connection between the GUT theory and its low-scale realization via a full renormalization procedure.