First principle qqbar Salpeter equation, spectrum and Regge trajectories
  Starting from a first principle Salpeter equation we computed the heavy-heavy, light-light and heavy-light quarkonium spectrum and the ground light-light Regge trajectories. We neglect spin-orbit structures and exclude from our treatment the light pseudoscalar states which in principle would require the use of the full Bethe-Salpeter equation due to the chiral symmetry breaking problem. We found a good agreement with the experimental meson masses and straight Regge trajectories with the right slope and intercepts. Since the parameter are completely specified by the heavy quarkonium spectrum and by high energy scattering, for what concerns light-light and light-heavy quarkonium systems our calculation is essentially parameter free. 
M. Baldicchi, G.M. Prosperi