Lambda_msbar from the static potential for QCD with n_f=2 dynamical quark flavors

Abstract

We determine Lambda_msbar for QCD with n_f=2 dynamical quark flavors by fitting the Q-Q-bar static potential known analytically in the perturbative regime up to terms of O(alpha_s^4) and ~alpha_s^4 ln(alpha_s) to corresponding results obtained from lattice simulations. This has become possible, due to recent advances in both perturbative calculations, namely the determination and publication of the last missing contribution to the Q-Q-bar static potential at O(alpha_s^4), and lattice simulations with n_f=2 dynamical quark flavors performed at the rather fine lattice spacing of a~0.042 fm. Imposing conservative error estimates we obtain Lambda_msbar=315(30) MeV.

25 pages, 7 figures; reference added