Mass-dependent β-function

Threshold effects related to fermion masses are considered for an all-order β-function based on a background field momentum subtraction scheme. Far away from all thresholds, the suggested β-function reduces to the conjectured all-order form inspired by the Novikov-Shifman-Vainshtein-Zakharov β-function of N=1 supersymmetric gauge theories with a fixed integer number of fermion flavors. At (formally) infinite masses the corresponding pure Yang-Mills β-function is recovered. We discuss applications to the phase diagram of non-Abelian field theories.