Screened massive expansion of Schwinger-Dyson equations

TL;DR

This paper presents a formal derivation of the screened massive expansion using Schwinger-Dyson equations, clarifies existing issues, and extends the method to higher loops and more general amplitudes, enhancing the theoretical framework.

Contribution

It provides a general formal derivation of the screened massive expansion and extends it to two-loop levels and non-generating functionals, addressing known issues.

Findings

Clarifies issues in the screened massive expansion

Establishes a framework for two-loop extensions

Derives a one-loop expansion for the gluon propagator

Abstract

A general formal derivation of the screened massive expansion is provided by Schwinger-Dyson equations. Some known issues of the expansion are clarified and a more general framework is established for a natural extension of the method to two-loop or to amplitudes which are not directly defined by a generating functional. For instance, a one-loop screened expansion is given for the effective gauge-parameter-independent gluon propagator which arises from the pinch-technique.