The Two-Loop Massless Off-Shell QCD Operator Matrix Elements to Finite Terms

Understand

We calculate the unpolarized and polarized two--loop massless off--shell operator matrix elements in QCD to $O(\varepsilon)$ in the dimensional parameter in an automated way.

• Here we use the method of arbitrary high Mellin moments and difference ring theory, based on integration-by-parts relations.
• This method also constitutes one way to compute the QCD anomalous dimensions.
• The presented higher order contributions to these operator matrix elements occur as building blocks in the corresponding higher order calculations up to four--loop order.