Phenomenology of theories of a composed Higgs

Abstract

The Standard Model (SM) of Particle Physics is an extremely successful description of the experimental data we have today. However, its limitations are apparent from the fact that it has a large number of arbitrary parameters. Most importantly, in the SM the electroweak scale is unstable, that is, it gives rise to the so-called hierarchy problem. A solution to this problem requires new physics at the TeV scale, which is precisely the energy scale being explored at CERN's Large Hadron Collider (LHC). In this project, we propose to study extensions of the SM that describe new physics at the TeV scale.Since the discovery of the Higgs Boson in 2012, the SM spectrum has been completed. The solution to the hierarchy problem mentioned above is typically twofold: if the Higgs boson is elementary, supersymmetry must be present on the TeV scale. Otherwise, the Higgs boson must be a composite state. In this project we focus on the second case.The composite Higgs models, in general, are associated with new physics at the TeV scale. Given that, in that case, the Higgs boson must also be a pseudo Nambu-Goldstone boson (pNGB), the result of the spontaneous breaking of a global symmetry, these new states resulting from the new symmetry are apparently inevitable. The absence of the discovery of these states, particularly at the LHC, is a problem with the composite Higgs models. However, a phenomenology focused on the Higgs boson and its couplings to other particles in the SM, is well defined. This will be the focus of this project: to study theoretical and phenomenological bases of these models, particularly in the era of high luminosity at the LHC.