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Quantum Chromodynamics

see also standard_model


Quantum chromodynamics is the correct model for strong interactions, which is one of the four known fundamental interactions1). It is a model in the framework of quantum field theory.

Strong interactions bind quarks together such that they form neutrons or protons. Additionally, they are also responsible for binding neutrons and protons to atomic nuclei together.

The particles that are responsible for strong interactions are called gluons, since they "glue" the quarks together. Formulated differently, gluons are for strong interactions what photons are for electromagnetic interactions

Gluons couple to all particles that carry the charge of quantum chromodynamics, which is known as color charge. In other words, only particles with color charge (quarks and gluons) take part in strong interactions. This is again analogous to electromagnetic interactions since only particles that carry electric charge take part in electromagnetic interactions, i.e. couple to photons.


The best resource for the correct Feynman rules of QCD is A resource for signs and Feynman diagrams of the Standard Model by Jorge C. Romao. The thing is that there are many different conventions and these authors develop a notation that allows us to map them all onto each other.

  • The Black Book of Quantum Chromodynamics by John Campbell, Joey Huston, and Frank Krauss

Why is it interesting?

Quantum Chromodynamics (QCD) is the best theory of strong interactions that we have. Strong interactions is another name for one of the four fundamental forces that know. (The others are: the weak force, the electric force and gravity).

It's a crucial part of the standard model and describes accurately how, for example, quarks interact with each other.

The other three are electromagnetic interactions, weak interactions, and gravity.
models/standard_model/qcd.txt · Last modified: 2018/12/19 11:00 by jakobadmin