Buchmüller-Grunberg-Tye-type potential consistent with smaller values ofΛMS―

The Buchmüller-Grunberg-Tye potential for heavy quarkonia is modified so that it is consistent with the smaller values of the scale parameter ${\Lambda }_{\overline{\mathrm{MS}}}$, 50-100 MeV, as suggested recently. ($\overline{\mathrm{MS}}$ denotes the modified minimal-subtraction scheme.) The potential has a practically asymptotic region above 2-3 GeV in momentum space, or at distances shorter than 0.05-0.1 fm. This is consistent with the experimentally measured spectra of $\psi$ and $\Upsilon$ families and their leptonic decay widths. It is shown that the spectra of $\mathrm{tt}$ states would provide a nice way to determine ${\Lambda }_{\overline{\mathrm{MS}}}$ in the range quoted above.