No-$\pi$ schemes for multi-coupling theories

Abstract

We show that even $\zeta$-functions may be removed from the $\beta$-functions of general multi-coupling theories up to high loop order by means of coupling redefinitions. For theories whose $\beta$-function is determined by the anomalous dimensions of the fields, such as supersymmetric theories, this corresponds to a renormalisation scheme change to a momentum subtraction scheme.

63 pages, LaTeX, diagrams produced using tikz. Minor corrections made, note added