The Standard Model (SM) of Particle Physics is an extremely successful description of the experimental data we have today. However, its limitations are apparent because it has a large number of arbitrary parameters. On the other hand, there are many evidences for the existence of dark matter (DM) and they are indisputable. Dark matter corresponds to more than 80% of the matter observed in the universe. However, the SM does not contain any candidate particles for DM, so incorporating it requires a theory beyond SM. Ad hoc theories extending the SM only to accommodate DM exist in abundance and if they serve as a guide to phenomenology, they do not make predictions regarding the rest of the particle physics.Another problem of SM is the fact that the electroweak scale is unstable, which gives rise to the so-called hierarchy problem. The solution of this problem requires new physics in the TeV scale, which is precisely the energy scale being studied in the Large Hadron Collider (LHC) of CERN. In this project we propose to study extensions of the SM that describe new physics in the TeV scale, solving the hierarchy problem, and producing natural candidates for DM. In particular, we will focus on the so-called Twin Higgs (TH) model. In this theory, the Higgs boson is light, since it is a pseudo Nambu-Goldstone boson (pNGB), resulting from the spontaneous breaking of a global symmetry. The model predicts the existence of a "twin" sector, a nearly exact copy of the standard model, both in fermionic and gauge representations. The TH model was proposed to solve the hierarchy problem. However, the necessary existence of the twin sector allows the possibility of having DM without the need to introduce additional elements. In particular, given the right conditions for the Higgs sector of the theory, nucleons in the twin sector are excellent candidates for DM.There are several possibilities to take advantage of the twin sector of the TH to incorporate DM. For the project, the student will study in depth the possibilities that already exist in the literature, and at the end he will make an original contribution.
News published in Agência FAPESP Newsletter about the scholarship: