New Pathways in High-Energy Physics II pp 213-230 | Cite as

# Infrared Singularities of Non-Abelian Gauge Theories

## Abstract

For some time, we have been interested in the infrared structure of non-Abelian gauge theories.^{1,2} There are prominent infrared singularities near the mass shell only when the local gauge invariance is unbroken, as in quantum chromodynamics (QCD). We (and other authors^{3,4}) began with the straightforward calculation of Feynman graphs, in leading-logarithm approximation, regulating the infrared singularities either by staying slightly off the mass shell by an amount characterized by a small mass μ, or by introducing a fictitious (group-symmetric) vector mass μ in the Feynman gauge. The results turned out to be much simpler than the complexity of the calculations suggested, and are characterized by certain properties of exponentiation and factorization which are reminiscent of the corresponding results for the Abelian case (quantum electrodynamics, or QED). These properties are summarized by a differential equation in μ (the infrared cutoff) which looks very much like a renormalization group (RG) equation with a special type of anomalous dimension generated by the near-mass-shell infrared singularities.

## Keywords

Anomalous Dimension Mass Shell Soft Gluon Gluon Propagator Hadronic Physic## Preview

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## References

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