IMPROVING LARGE-ORDER PERTURBATIVE EXPANSIONS IN QUANTUM CHROMODYNAMICS

We consider divergences of the perturbative expansions in large orders in quantum electro- and chromodynamics and concentrate on the dependence of large-order contributions on the choice of the normalization point of coupling constants. We find that for sign-alternating series the predictive power of perturbation theory as measured by the minimal term of an asymptotic expansion can be drastically improved by a proper choice of the normalization point. In particular, this allows the elimination of the leading uncertainty of perturbative expansions in quantum chromodynamics.