Spectroscopy, leptonic decays and the nature of heavy quarkonia

We examine the electronic width ratios of ϒ resonances below the BB¯ threshold by means of an effective (Cornell-type) QCD potential incorporating 1/mb corrections obtained from a prior fit to the bottomonium spectrum. From our analysis we conclude that the ϒ(2S) and ϒ(3S) states should belong to the strong-coupling (nonperturbative) regime while the ϒ(1S) state should belong to the weak-coupling (perturbative) regime, in agreement with a previous study based on radiative decays.