New Physics and Vector Like Fermions
PT-CERN Call 2021/2
Instituto Superior Técnico (Universidade de Lisboa)
CFTP - Centro de Física Teórica de Partículas
The main focus of this thesis proposal will be on the development of models with vector-like fermions (VLFs), but multi-Higgs models shall also be explored. The topics to be covered are, amongst other, the development and use of (new) concrete tools to test physics beyond the SM and explore NP models which are consistent with the Electro Weak Precision Measurements (EWPM) of the current and of future data, coming from LHC or others. While developing these NP models we aim to achieve exciting and impactful predictions which may be able to point experimentalists to look for new exotic phenomena. We shall also focus on very sensitive CP violation measuring parameters such as ε_K, ε’/ε or others, which may pose strict restrictions to these models and their content. Additionally, in our analysis of models, we will use other powerful tools based on weak-basis invariants. We will look for alternative forms of generating the mixings and masses of the lighter quarks with the introduction of vector-like quarks (VLQs) and shall look for new possible sources of CP-violation in both the quark and lepton sector with VLFs. The CKM unitarity problem, is also an important problem which we will be addressed in the context of VLQs as well as the NP effects it entails (e.g. flavour changing neutral currents). Currently, one of the main issues at the LHC is the search for new heavy fermions, e.g. quarks with masses beyond the top quark, as is the case of a heavy-top and which occurs naturally in models with VLQs in the up sector, or in the case of the leptons, the search for heavy Majorana neutrinos. With this in mind, we will be studying predictions for processes, possibly, to be witnessed at the LHC, as e.g. the hypothetical decays of these new heavy fermions. Thus, a strong interaction with experimentalists at LIP/CERN will be required. The student will conduct research at both the Centro de Física Teórica de Partículas (Lisbon) and Instituto de Física Corpuscular (Valencia).