Theory
Particle physics seeks to answer two questions:
- What are the fundamental (smallest) building blocks from which all matter is made?
- What are the interactions between them that govern how they combine and decay?
Click on the
standard model chart for more information. The name given
to the theory that best incorporates all observations to date
in the particle realm is "the Standard
Model".
This theory describes the strong, weak, and electromagnetic interactions of quarks and gluons. It also describes the weak and electromagnetic interactions of leptons, the particles that do not participate in strong interactions.
Gravitational interactions have yet to be successfully incorporated into the quantum field theory and are a tiny effect in high energy particle collisions, so are ignored in the Standard Model.
A fifth force is needed to complete our understanding of particle masses.
For a lively introductory tutorial on the content of the Standard Model go to the Contemporary Physics Education Project's Particle Adventure.
Particle physics theories are written in mathematical language called relativistic quantum field theory. This builds on the two major early twentieth century advances in physics, relativity and quantum mechanics.
These advances have withstood the test of many experiments and are now well established as the proper description of processes at atomic and sub-atomic scales, even though they contain ideas and effects that, in the light of our human scale experience, seem counter-intuitive.
