Determination of αS from hadronic event shapes in e+e- annihilation at 192 ≤ √s ≤ 208 GeV

Results are presented from a study of the structure of high energy hadronic events recorded by the L3 detector at root(s) greater than or equal to192 GeV. The distributions of several event shape variables are compared to resummed O(alpha(s)(2)) QCD calculations. We determine the strong coupling constant at three average centre-of-mass energies: 194.4, 200.2 and 206.2 GeV. These measurements, combined with previous L3 measurements at lower energies, demonstrate the running of alpha(s) as expected in QCD and yield alpha(s)(m(Z)) = 0.1227 +/- 0.0012 +/- 0.0058, where the first uncertainty is experimental and the second is theoretical. (C) 2002 Published by Elsevier Science B.V.