Long-Distance Behavior of the Invariant Charge in Non-Abelian Gauge Theories

Abstract

The long-distance behavior of the invariant charge is investigated. For massive quarks, the gluon-quark-antiquark charge is equal to the massless Yang-Mills charge. This result reflects the fact that the infrared limit is reached only as the gluon and quarks approach their mass shell at the same rate. A nonperturbative scheme in terms of the invariant charge, that could explicitly display the infrared structure of non-Abelian theories, is proposed.