Quark Confinement

Quark Confinement:
There can exist no free quarks, i.e. quarks by themselves. All quarks must be bound to another quark or
antiquark by the exchange of gluons. This is called quark confinement. The exchange of gluons produces
a color force field, referring to the assignment of color charge to quarks, similar to electric charge.
The color force field is unusual in that separating the quarks makes the force field stronger (unlike
electromagnetic or gravity forces which weaken with distance). Energy is needed to overcome the color
force field. That energy increases until a new quark or antiquark is formed (energy equals mass, E=mc2).

Two new quarks form and bind to the old quarks to make two new mesons. Thus, none of the quarks were
at anytime in isolation. Quarks always travel in pairs or triplets.