Bjorken sum rule and perturbative QCD frontier on the move

作者：Pasechnik Roman S^*; Shirkov Dmitry V; Teryaev Oleg V

来源：Physical Review D - Particles, Fields, Gravitation and Cosmology, 2008, 78(7): 071902.

DOI：10.1103/PhysRevD.78.071902

The reasonableness of the use of perturbative QCD notions in the region close to the scale of hadronization, i.e., below less than or similar to 1 GeV is under study. First, the interplay between higher orders of pQCD expansion and higher-twist contributions in the analysis of recent Jefferson Lab (JLab) data on the generalized Bjorken sum rule function Gamma(p-n)(1)(Q(2)) at 0.1 < Q(2)< 3 GeV(2) is studied. It is shown that the inclusion of the higher-order pQCD corrections could be absorbed, with good numerical accuracy, by change of the normalization of the higher-twist terms. Second, to avoid the issue of unphysical singularity (Landau pole at Q=Lambda similar to 400 MeV), we deal with the ghost-free analytic perturbation theory (APT) that recently proved to be an intriguing candidate for a quantitative description of light quarkonia spectra within the Bethe-Salpeter approach. The values of the twist coefficients mu(2k) extracted from the mentioned data by using the APT approach provide a better convergence of the higher-twist series than with the common pQCD. As the main result, a good quantitative description of the JLab data down to Q similar or equal to 350 MeV is achieved.

• 出版日期2008-10