Precision computation of a low-energy reference scale in quenched lattice QCD

We present results for the reference scale ro in SU(3) Lattice Gauge Theory for beta = 6/g(0)(2) in the range 5.7 less than or equal to beta less than or equal to 6.57. The high relative accuracy of 0.3-0.6% in r(0)/a was ach ieved through good statistics, the application of a multi-hit procedure and a variational approach in the computation of Wilson loops. A precise defin ition of the force used to extract ro has been used throughout the calculat ion which guarantees that r(0)/a is a smooth function of the bare coupling and that subsequent continuum extrapolations are possible. The results are applied to the continuum extrapolations of the energy gap Delta in the stat ic quark potential and the scale L-max/r(0) used in the calculation of the running coupling constant. (C) 1998 Elsevier Science B.V.