Perturbative QCD predictions for the small x behaviour of unpolarized and polarized deep inelastic scattering structure functions

الأصل · EN

The perturbative QCD predictions for the small x behaviour of the nucleon structure functions F₂,ₗ(x,Q²) and g₁(x,Q²) are summarized. The importance of the double logarithmic terms for the small x behaviour of the spin structure function g₁(x,Q²) is emphasised. These terms correspond to the contributions containing the leading powers of αₛ ln(1/x)² at each order of the perturbative expansion. In the non-singlet case they can be approximately accounted for by the ladder diagrams with quark (antiquark) exchange. We solve the corresponding integral equation with the running coupling effects taken into account and present estimate of the effective slope controlling the small x behaviour of the non-singlet spin structure function g₁(x,Q²) of a nucleon.