Canonical flow in the space of gauge parameters

We show that the gauge dependence of one-particle irreducible amplitudes in the $SU(N)$ Yang–Mills theory is generated by a canonical flow with respect to the extended Slavnov–Taylor identity induced by the transformation of the gauge parameter $\alpha$ under the BRST symmetry. For linear covariant gauges, the analytic expansion in $\alpha$ of one-particle irreducible amplitudes is given in terms of coefficients evaluated in the Landau gauge and of derivatives with respect to $\alpha$ of the generating functional of the flow. We consider an application to the gauge flow of the gluon propagator.