Anomalous dimension of non-singlet quark currents at O(1/Nf2) in QCD

We compute the O(1/Nf2) corrections to the flavour non-singlet quark bilinear currents in QCD in arbitrary spacetime dimensions. Hence, the anomalous dimension of the QED current ψ̄σμνψ is deduced at four loops in the MS scheme up to one unknown parameter.