Five-loop fermion anomalous dimension for a general gauge group from four-loop massless propagators

Abstract We extend the O α s 5 $$ \mathcal{O}\left({\alpha}_s^5\right) $$ result of the analytic calculation of the quark mass anomalous dimension in pQCD [1] to the case of a generic gauge group. We present explicit formulas which express the relevant renormalization constants in terms of four-loop massless propagators. We also use our result to shed new light on the old puzzle of the absence of even zetas in results of perturbative calculations for a class of physical observables