color charge

The term color charge is used for a property of gluons and quarks; it is something like electrical charge, but with more than two polarities. It is an aspect of the theory of the strong force, the theory termed quantum chromodynamics (QCD). It can be thought of as having six polarities, termed colors. (The use of color, and colors to name them is just a convenience, there is no connection with visible light colors we perceive, other than some similarity in the manner in which they combine.) Each color attracts any of the other colors but repel their own, i.e., the strong force. Three of the colors are present in quarks, individually termed red, green, and blue. The other three are present in antiquarks (antimatter quarks), and are termed anticolors, individually, anti-red, anti-green, and anti-blue. Just as electric charges tend to be balanced locally such that they appear neutral from a distance, the color charges in each others' presence nullify their effects, such a balance termed no color. Equal amounts of a color and its anticolor neutralize each other in this manner, and also, equal amounts of the three colors together or the three anticolors together do so. A quark of any flavor can have any one of the three colors, and an antiquark can have any of the anticolors, and the color of a particular quark can be changed. A baryon (which consists of three quarks) has a quark of each color, which binds them together. A meson is a quark and antiquark, one of a color and the other an antiquark with its corresponding anticolor. (Mesons decay after a very short lifetime, sometimes through quark-antiquark annihilation.) The strong force has a particle aspect (just as electromagnetic radiation has the photon), termed the gluon. The gluon, like the photon, has no mass and travels the speed of light (from quark to quark), but unlike the photon, it carries colors, constantly changing the colors of the quarks within a baryon: for example, a gluon from a red quark to a blue quark carries both the red and anti-blue colors, leaving the quark it came from as blue, and changing the quark it is going to, to red.