In the Standard Model, the Higgs boson is responsible for giving particles mass through a process called the Higgs mechanism. However, the interactions between the Higgs boson and usual quarks are determined by Yukawa couplings, which means that the strength of their interactions depends on their mass. In contrast, vector-like quarks are expected to have a more “vector” coupling with the Higgs boson, which would make their interactions independent of their mass. This property could potentially make them easier to detect experimentally. In this chapter, we develop the theoretical framework of such exotic heavy quarks both in the standard model and beyond it such as the two Higgs doublets model (2HDM). This chapter introduces a Lagrangian which follows the most generic concept of the Standard Model which is consistent with the basics, and then we explore the consequences of identifying the eigenstates and interactions with SM-VLQ. We also provide a detailed description of the full interaction in the 2HDM mass basis. We shortly comment on the production of heavy quark pairs at the LHC.
Part of the book: Quantum Entanglement in High Energy Physics