MASS-SPECTRA AND LEPTONIC DECAY WIDTHS OF HEAVY QUARKONIA

A nonrelativistic Hamiltonian with plausible spin dependent correction s is proposed for the quarkonia below their respective strong decay th resholds. With only six free parameters this model reproduces the nine known masses of the bottomonia within about 1 MeV, the six known mass es of the charmonia within a few MeV and the five known leptonic decay widths of the S-3(1) states within about 20 %. The model is then used to. predict the masses of the remaining 43 quarkonia (some of them fo r the first time) and of the leptonic decay widths of the two (1)So((b ) over bar c) states. Comparison with some other models is made.