Mass spectrum of ground state charmonium states in relativistic quark model

Meson physics and the strong interactions have been intimately connected since pions were first introduced by Yukawa to explain the internucleon force. Since then our knowledge of mesons and strong interactions has undergone several revisions due to continuously increasing huge amount of experimental data. Our present understanding of the strong interactions is that it is described by the QCD which describes the interactions of quarks and gluons