QCD pressure: Renormalization group optimized perturbation theory confronts lattice

The quark contribution to the QCD pressure, Pq, is evaluated up to next-to-leading order (NLO) within the renormalization group optimized perturbation theory (RGOPT) resummation approach. To evaluate the complete QCD pressure we simply add the perturbative NLO contribution from massless gluons to the resummed Pq. Despite this unsophisticated approximation our results for P = Pq + Pg at the central scale M ∼ 2πT show a remarkable agreement with lattice predictions for 0.25 ≲ T ≲ 1 GeV. We also show that by being imbued with RG properties, the RGOPT produces a drastic reduction of the embarrassing remnant scale dependence that plagues both standard thermal perturbative QCD and hard thermal loop perturbation theory applications.