Quarkonium Spectroscopy and Perturbative QCD: A New Perspective

We report new aspects of the recent theoretical progress in heavy quarkonium physics. (1) Contrary to wide beliefs, the gross structure of the bottomonium spectrum is described well by the non-relativistic boundstate theory based on perturbative QCD. (2) This leads to a new physical picture of the bottomonium states: the boundstate mass is composed mainly of the self-energies of b and bbar accumulated inside the boundstate. (3) A connection to the conventional phenomenological potential-model approaches is provided