164 research outputs found
Four-loop beta function and mass anomalous dimension in Dimensional Reduction
Within the framework of QCD we compute renormalization constants for the
strong coupling and the quark masses to four-loop order. We apply the DR-bar
scheme and put special emphasis on the additional couplings which have to be
taken into account. This concerns the epsilon-scalar--quark Yukawa coupling as
well as the vertex containing four epsilon-scalars. For a supersymmetric Yang
Mills theory, we find, in contrast to a previous claim, that the evanescent
Yukawa coupling equals the strong coupling constant through three loops as
required by supersymmetry.Comment: 15 pages, fixed typo in Eq. (18
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