Dressed Skeleton Expansion and the Coupling Scale Ambiguity Problem*

We present the Dressed Skeleton Expansion (DSE) as a method of perturbative calculation in quantum field theories, without the scale ambiguity problem. We illustrate the application of the DSE method to the two-particle elastic scattering amplitude in 4: theory, and compare this method with the usual perturbative expansion, combined with scale setting prescriptions. Submitted to Physics Letters B *Work supported in part by the National Science Foundation, and by Department of Energy contract DE-AC03-76SF00515. Perturbative calculations in quantum field theories are usually expressed as a power seriesin a fixed coupling constant. At high transferred squared momentum, the fixed coupling constant must be replaced by a running coupling constant. This : procedure is usually referred to as the renormalization-group-improved perturbation, which leads to the absorption of the large logarithmic terms into the running coupling constant. In simple words, given a truncated series of a physical quantity expanded in powers of a coupling constant in a given scheme: & = Q’(P) [ro + n(p) 4.4 + . . .r&) an(p)1 , (1)