värivaraus

Värivaraus, often translated as "color charge," is a fundamental property of quarks and gluons in quantum chromodynamics (QCD), the theory of the strong nuclear force. It is analogous to electric charge in electromagnetism, but with a crucial difference: color charge comes in three types, conventionally referred to as red, green, and blue. Antiquarks carry the corresponding anticolors: anti-red, anti-green, and anti-blue.

The strong force, mediated by gluons, acts between particles that possess color charge. Unlike electric charge, which can be positive or negative, color charge is always present in combinations that are "colorless" or "white" in macroscopic terms. This confinement is why free quarks and gluons are not observed; they are always bound together in composite particles called hadrons. Hadrons are either baryons, composed of three quarks (one of each color: red, green, blue, forming white), or mesons, composed of a quark and an antiquark of a corresponding color-antcolor pair (e.g., red and anti-red, also forming white).

The concept of color charge was introduced to explain the behavior of certain hadrons, particularly the delta plus plus (Δ++) baryon, which was observed to have three identical up quarks within a confined space without violating the Pauli exclusion principle. The introduction of color charge as an additional quantum number for quarks resolved this issue, allowing for the existence of such composite particles. The mathematical framework describing the interactions of color charges is SU(3) gauge theory.