Evolution of Weinberg's gluonicCP-violation operator and gauge dependence

We compute the one-loop evolution of Weinberg's three-gluon $\mathrm{CP}$ violating vertex in a general $\alpha \ne 0$ gauge. We find that Weinberg's dimension-6 operator mixes with the Faddeev-Popov ghosts as well as with the quarks. Nevertheless the anomalous dimension of the three-gluon vertex is explicitly $\alpha$ independent. The result is a suppression factor for the neutron electric dipole moment rather than enhancement.