Nucleon Spin Sum Rules: Analysis Based on Analytic Approach in QCD

Abstract

We study the difference between the higher order analytic perturbation theory (APT) and the standard perturbative description when analysing recent Jefferson Lab (JLab) data on the first moments of spin structure functions g1p,n at 0.05 < Q2 < 3 GeV2. It has been shown that the values of higher twist parameters extracted from the data by using the APT approach provides better convergence of the higher-twist series than by common perturbative QCD. We obtain good quantitative description of all the JLab data sets down to Q 280 MeV.