Example of elementary particles collision at the LHC.

The main objective of this research area, also known as High Energy Physics is the most fundamental understanding of the constituents of nature and their basic interactions.

For fundamental constituents we understand the elementary particles, which are classified into two types: fermions and bosons. Currently, we know for basic interactions: weak and strong nuclear forces, the electromagnetic and the gravitational interactions. The current theory that describes the interactions between elementary particles (ignoring gravity) is the Standard Model. It results from Quantum Field Theory by considering certain special symmetries. In this model fermions appear in replicas of a family composed of the electron, the neutrino and up and down quarks (the constituents of protons and neutrons). The vector bosons are intermediaries of interactions and also there is a postulated boson scalar (Higgs boson) to explain the existence of mass of other elementary particles. The existence of the Higgs boson was recently confirmed by experiments at the Large Hadron Collider (LHC) at CERN.

Elementary particles of the Standard Model

The work of a physicist in this area can be purely theoretical: seeking mathematical tools to fill gaps in current knowledge of elementary interactions, testing the consistency of new theories or hypotheses as extra dimensions, supersymmetry, etc. It can also be experimental, ranging from the construction and operation of particle detectors of all sizes, to the interpretation of the data provided by these machines, trying to connect them with the various hypotheses existing in the theoretical field. In common, all physicists working in this area need to have a solid understanding of the fundamental theories of physics, especially quantum mechanics and relativity, and a great curiosity for understanding the innermost nature of matter.

### Research Perspectives

The successful experimental confirmation of the Standard Model helped formulate new questions that drive the research topics in the area. Among some of these issues are the following:

• precision tests of the Standard Model,

• stabilization the electroweak scale,

• the existence of new symmetries such as supersymmetry and gauge groups beyond the Standard Model,

• mechanisms of symmetry breaking and mass generation,

• the problem of mass and mixing of neutrinos,

• the problem of matter-antimatter asymmetry in the universe,

• the stability of the proton,

• the problem of confinement of quarks and the mass spectrum of QCD at low energies,

• candidates particles for dark matter,

• the existence of extra dimensions,

and so on.

Example of a Calabi-Yau space, studied in the context of compactifications of String Theory

There are also applications in condensed matter physics, for example, the quantum Hall effect and low dimensional systems.

Great experiments in physics take place today, as well as new experiments are planned for the coming years. These experiments have significant potential to lead to new discoveries. The UFABC has representatives in the CMS collaboration at CERN, which investigates high-energy collisions in the LHC accelerator, and in the Pierre Auger cosmic ray observatory, for example. Thus, the coming years should continue with an intense activity, both in experimental and theoretical field in the area of Elementary Particles and Fields.

**Interresting Links**

**Supervisors working in this field**

**Quantum Field Theory / Elementary Particles Phenomenology**

**Física Experimental de Altas Energias**