Asymptotic scaling of the heavy-quark potential in lattice QCD.

The scaling behavior of the heavy-quark {ital q{bar q}} potential is studied by measuring Wilson-line operator-operator correlations via extensive simulations on large lattices. By using large size loops (up to 16{times}12) and extracting the potential at large distance {ital R}{ge}4, we find that the string tension satisfies the two-loop asymptotic scaling within about 95% accuracy at the coupling {beta}=6.0, 6.1, 6.2 and {alpha} remains a constant. Thus the scaling of the string tension sets in at around {beta}=6. The obtained values {radical}{sigma} /{Lambda}{sub {ital L}}=78{plus minus}4 and {alpha}{congruent}0.54{plus minus}0.11 agree well with the potential-model analysis on the {ital c{bar c}} and {ital b{bar b}} systems. Among the existing underlying string theories, our results favor the Neveu-Schwarz string theory.