B-C SPECTROSCOPY

In the framework of potential models for heavy quarkonium the mass spectrum for the system (b̄c) is considered. Spin-dependent splittings taking into account a change of a constant for the effective Coulomb interaction between the quarks, and widths of radiative transitions between the (b̄c) levels are calculated. In the framework of QCD sum rules, the masses of the lightest vector Bc* and pseudoscalar Bc states are estimated, the scaling relation for leptonic constants of heavy quarkonia is derived, and the leptonic constant fBc is evaluated. © 1995 The American Physical Society.