"Massive" Perturbative QCD, regular in the IR limit
  The goal of research is to devise a modification of the perturbative QCD that should be regular in the low-energy region and could serve as a practical means for the analysis of data below 1 \GeV up to the IR limit. Recent observation of the four-loop pQCD series "blow-up" in the region below 1 \GeV for the Bjorken Sum Rule gave an impetus to this attempt. The proposed {\sf "massive analytic pQCD"} is constructed on the two grounds. The first is the pQCD with only one parameter added, the effective "glueball mass" $m_{gl}\lesssim 1 \GeV,$ serving as an IR regulator. The second stems out of the ghost-free Analytic Perturbation Theory comprising non-power perturbative expansion that makes it compatible with linear integral transformations. In short, the proposed MAPT differs from the minimal APT by simple ansatz $Q^2 \to Q^2+m_{gl}^2.$ 
D. V. Shirkov
hep-th hep-ph