Standard Model

The Standard Model is the theoretical framework that describes the fundamental particles of nature and the forces that act between them.

  • The Standard Model is a quantum field theory, which means that it uses the principles of quantum mechanics to describe the behaviour of matter and energy at the atomic and subatomic levels.
  • The Standard Model is based on two fundamental theories:
    • Quantum mechanics provides a description of the physical properties of nature as interactions between fields of energy at the scale of atoms and subatomic particles. It is the foundation of all quantum physics.
    • Special relativity is a theory of space and time developed by Albert Einstein in 1905. It states that:
      • The laws of physics are invariant (i.e., identical) in all inertial frames of reference.
      • The speed of light in a vacuum is the same for all observers, regardless of the motion of the light source or observer.
  • The Standard Model describes three of the four fundamental forces:
  • Despite its success, the Standard Model has a major limitation: it doesn’t describe gravity. This is because gravity is not compatible with the principles of quantum mechanics at very small scales. Scientists are still searching for a more comprehensive theory, sometimes called a “Theory of Everything,” that can unify the Standard Model with gravity.
  • The Standard Model describes 17 fundamental particles
    • Quarks: Up, down, charm, strange, top, and bottom.
    • Leptons: Electron, muon, tau, and their 3 corresponding neutrinos.
    • Bosons: Photon, gluon, W and Z bosons, and the Higgs boson.
  • Arguably, the Standard Model stands as the most successful theory created so far by human beings in our attempts to comprehend the totality of existence – the Universe, the world around us, and every aspect of our own physical being.
  • Whilst the model has been able to explain the presence of three of the the four fundamental forces, the behaviour of subatomic particles, and the structure of the atom, it remains a work in progress, with physicists continuously seeking to refine it.
  • The following scientists have received a Nobel Prize for their work on the Standard Model:
    • Richard Feynman, Julian Schwinger, and Yoichiro Nambu (1965 Nobel Prize in Physics) for their work on quantum electrodynamics.
    • Murray Gell-Mann (1969 Nobel Prize in Physics) for his classification of elementary particles.
    • Steven Weinberg, Sheldon Glashow, and Abdus Salam (1979 Nobel Prize in Physics) for their unification of the weak and electromagnetic forces.
    • Peter Higgs and François Englert (2013 Nobel Prize in Physics) for their discovery of the Higgs boson.
Related diagrams

Each diagram below can be viewed on its own page with a full explanation.

References