Inverse scattering and the Υ family

A quarkonium potential is constructed with the help of masses and leptonic widths of the Υ(lS‐4S) levels using the inverse scattering formalism. This potential agrees at all interquark separations beyond 0.06f with one constructed earlier from ψ and ψ′, providing further evidence for flavor independence of the QQ interaction. Comparison with other a priori potentials suggests that tests for a short‐range Coulomb interaction (as predicted by QCD) will have to rely primarily on more precise values for Γ(Υ→e+e−), on measurement of the 2S‐2P spacing (predicted to be about 120 MeV for a short‐range Coulomb‐like interaction or in the inverse scattering formalism but about 150 MeV for an effective power‐law potential), and on the discovery of heavier quarks.