OPE of the energy-momentum tensor correlator and the gluon condensate operator in massless QCD to three-loop order

Understand

The correlator of two gluonic operators plays an important role for example in transport properties of a Quark Gluon Plasma (QGP) or in sum rules for glueballs.

• In [1] an operator product expansion (OPE) at zero temperature was performed for the correlators of two scalar operators $O_1=-\frac{1}{4} G^{\mu \nu}G_{\mu \nu}$ and two QCD energy-momentum tensors $T^{\mu\nu}$.
• There we presented analytical two-loop results for the Wilson coefficient $C_1$ in front of the gluon condensate operator $O_1$.
• In this paper these results are extended to three-loop order.