Solutions to the Schwinger-Dyson equation for the gluon and their implications for confinement

Abstract

Using the Schwinger-Dyson equations the possible infrared behaviour of the gluon propagator is studied. Previous work performed in axial gauges is reviewed, the approximations needed detailed and the difficulties of their justification discussed. We then turn to the Landau gauge and investigate the possibility of a gluon propagator less singular than $1/p^{2}$ when $p^{2} \rightarrow 0$. We find that this infrared softened behaviour of the gluon propagator is inconsistent; only an infrared enhanced gluon, as singular as $1/p^{4}$ when $p^{2} \rightarrow 0$ is consistent with the truncated Schwinger-Dyson equation. The implications for confinement and for the modelling of the Pomeron are discussed.