Quark-antiquark spectroscopy and asymptotic freedom

The cc¯ and bb¯ spectra are used to restrict the parameters of a QCD-inspired linear plus Coulomb potential. The potential incorporates a running coupling constant α(r), which is controlled by a parameter b. This parameter is virtually undetermined by the cc¯ and bb¯ spectra. The spectra are extrapolated to the tt¯ regime for a variety of acceptable potentials or b values. It is shown how minimal tt¯ measurements will restrict α(r) and determine ${\Lambda }_{\mathrm{MS}\mathrm{¯}}$ (where MS¯ denotes the modified minimal-subtraction scheme).