Bjorken polarised sum rule with IR-finite QCD coupling

We evaluate the Bjorken polarised sum rule (BSR) Γ‾₁^p−n(Q²) with truncated Operator Product Expansion (OPE) up to the dimension D=4 terms; the leading-twist (D=0) contribution is evaluated with a renormalon motivated resummation, where we use the IR-finite running coupling free of Landau singularities. The free residue parameters at the D=2 and D=4 terms are then extracted by fits to the experimental BSR data. In comparison to the case when perturbative QCD coupling is used in this approach (cf. Refs. [1,2]), many advantages become manifest in the present case: (a) no regularisation in the resummation integral is needed; (b) the Q²-interval in the fit can be significantly extended to lower Q²-values; (c) the extracted residue parameter values are more stable, this being reflected in the significantly reduced experimental uncertainties of these values and the suppressed (almost negligible) central extracted value of the D=4 residue parameter (μ₆).