Evaluation of Bjorken polarised sum rule with a renormalon-motivated approach

We use the known renormalon structure of Bjorken polarised sum rule (BSR) Γ‾₁^p−n(Q²) to evaluate the leading-twist part of that quantity. In addition, we include D=2 and D=4 Operator Product Expansion (OPE) terms and fit this expression to available experimental data for inelastic BSR. Since we use perturbative QCD (pQCD) coupling, which fails at low squared spacelike momenta Q²≲1GeV² due to Landau singularities, the fit is performed for Q²≥Q_min² where Q_min²≈(1.7±0.3)GeV². Due to large BSR experimental uncertainties, the extracted value of the pQCD coupling has very large uncertainties, especially when Q_min² is varied. However, when we fix the pQCD coupling to the known world average values, the D=2 and D=4 residue parameters can be determined within large but reasonable uncertainties.