Quarkonium Mass Splitting Revisited: Effects of Closed Mesonic Channels

Abstract

Modifications of the mass spectrum the quarkonium induced by its virtual dissociation into a pair of heavy mesons is considered. Coupling between quark and mesonic channels results in noticeable corrections to spin-dependent mass splitting. In particular, the observable hierarchy of mass splittings in the ${\chi }_c,{\chi }_b$ and ${\chi }_b^{\prime }$ multiplets is reproduced.

Comments: 9 pages, plain LaTeX