SOFT DYNAMICS AND GAUGE-THEORIES

Infrared divergences obscure the underlying soft dynamics in gauge the ories. They remove the pole structures associated with particle propag ation in the various Green's functions of gauge theories. Here we pres ent a solution to this problem. We give two equations which describe h ow charged particles must be dressed by gauge degrees of freedom. One follows from gauge invariance, the other, which is new, from velocity superselection rules familiar from the heavy quark effective theory. T he solution to these equations in the Abelian theory is proven to lead to on-shell Green's functions that are free of soft divergences at al l orders in perturbation theory.