On the effective light-cone QCD-Hamiltonian
  Taking the effective interaction between a quark and an anti-quark from previous work, the dependendence on a regularization scale is removed in line with the renormalization group. In order to emphasize the essential point, the full spinor interaction is replaced by a model which includes only the Coulomb and the hyperfine interaction. By adjusting the effective quark masses, the only free parameters of the theory, the mass and the size of the pion are reproduced, as well as the mass of all other pseudo-scalar mesons. Estimates for the vector mesons are close to the empirical values. The model exposes screening rather than strict confinement. The ionization thresholds are in general much larger than the pion mass. 
Hans-Christian Pauli (MPI Kernphysik, Heidelberg)