The Three Loop On-Shell Renormalization of QCD and QED

摘要

The authors describe a calculation of the on-shell renormalization factors in QCD and QED at the three loop level. Explicit results for the fermion mass renormalization factor Zm and the on-shell fermion wave function renormalization constant Z{sub 2} are given. They find that at theta(alpha{sub 3}{sup 3}) the wave function renormalization constant Z{sub 2} in QCD becomes gauge dependent also in the on-shell scheme, thereby disproving the gauge-independence conjecture based on an earlier two-loop result. As a byproduct, they derive a theta(alpha{sub s}{sup s}) contribution to the anomalous dimension of the heavy quark field in HQET.