Meson Spectrum and the Glueball
  The formation and spectrum of two-particle bound states are investigated within a simple relativistic quantum field model with the Yukawa-type interaction. Within this approach, relatively weakly interacting quarks and gluons form stable bound states under the analytic confinement. By introducing a minimal set of free parameters (the quark masses, the coupling constant and the confinement 'radius') and by solving the Bethe-Salpeter equation with one-gluon exchange, we satisfactorily explain the experimental data for most known mesons and the glueball. 
G.Ganbold