Because of quark confinement we know that as we try to separate quarks appart the energy required will increase, but if the force is strong enough (I do not know if possible in the lab, but at least could happen near a blackhole horizon if one the quarks enters the black hole) part of that energy is used to form a new quark pair so that the two original ones will still be confined.
My question is has this been observed experimentally or is it only a prediction of the standard (or some other) model?
