Two-Loop QCD Renormalization and Anomalous Dimension of the Scalar Diquark Operator

The renormalization of the scalar diquark operator and its anomalous dimension is calculated at two-loop order in QCD, enabling higher-order QCD studies of diquarks. As an application of our result, the two-loop diquark anomalous dimension in the $\bar{{\rm MS}}$ scheme is used to study the QCD renormalization scale dependence of diquark matrix elements of the $\Delta S=1$ effective weak Hamiltonian.