A nonperturbative treatment of radiative decays and the relativistic kinetic energy in heavy quarkonia

Using a “regularized potential” we solve the Schrödinger equation including all spin dependent interactions nonperturbatively and calculate the radiative decays of heavy quarkonia. The influence ofS-D mixing due to the tensor term is discussed. Applying the variational approach we investigate the influence of the relativistic kinetic energy on the bound state masses.