Quark confinement

Quarks are not observed as free particles under ordinary conditions. As a quark and antiquark are pulled apart, the energy in the field between them grows. Once enough energy is available, producing a new quark–antiquark pair becomes energetically favorable: the field “breaks,” and the quarks rearrange into color-neutral hadrons. This is a simplified picture of confinement, not a way to obtain an isolated quark.