Quantum chromodynamics

Quantum chromodynamics or QCD is the theory of the strong nuclear interaction between quarks and gluons. These are the fundamental particles that make up the composite hadrons, such as the protons, neutrons and the pion. Quantum chromodynamics is a gauge theory with the symmetry group SU (3). There is a quantum chromodynamics analog of electric charge known as color. The force carrier for quantum chromodynamics is the gluon, like the photon of electromagnetism in quantum electrodynamics. Quantum chromodynamics is an important constituent of the Standard Model of particle physics. There has also been a large amount of experimental evidence for Quantum chromodynamics over the years. 

Color confinement

Color confinement is a consequence of the constant force between two color charges as they are separated. More energy is needed to increase the separation of two quarks within a hadron. Eventually, this energy becomes so great that it produces a quark-antiquark pair.  The initial hadron is turned into a pair of hadrons. This will be instead of producing an isolated color charge. Color confinement is well established from lattice QCD. 

Asymptotic freedom

There is a steady reduction in the strength of interactions between quarks and gluons as the energy  scale of those interactions increases. There would be a corresponding length scale decrease as the energy scale of the interaction increases. The asymptotic freedom of Quantum chromodynamics was discovered in 1973 by David Gross and Frank Wilczek. It was also discovered independently by David Politzer, in the same year.  These three figures shared the 2004 Nobel Prize in Physics for this work.