New extended Crewther-type relation and the consequences of multiloop perturbative results

Understand

We discuss the current status of the investigations of the conformal symmetry breaking contributions to three forms for the QCD generalizations of the Crewther relation.

• The new third form of the extension of this relation is considered in more detail.
• Particular attention is paid to the discussions of the applications of the $\beta$-expansion formalism proposed previously by one of us (SVM).
• Several relations between 5-loop contributions to the Adler D-function $D^{NS}_{A}$ and to the polarized Bjorken sum rule $S_\text{Bjp}$ are presented.