Light-light and heavy-light mesons spectra from nonperturbative QCD

Properties of light-light mesons are described by the effective Hamiltonian with spinless quarks derived from QCD. The spectrum is computed by the WKB method and shown to reproduce the celebrated linear Regge trajectories even for the lowest levels. The correct string slope of the trajectories naturally appears in the present approach as the string dynamics is taken into account properly. Similar method is applied to heavy-light mesons and a set of corrections to the Hamiltonian is taken into account including spin-spin and Tomas spin-orbit interactions. The numerical results for the spectrum are compared with the experimental data and with the results of recent lattice calculations.