The constraints on the non-singlet polarised parton densities from the infrared-renormalon model

Abstract

Using the infrared-renormalon approach, we obtain the constraints on the next-to-leading order non-singlet polarised parton densities. The advocated feature follows from the consideration of the effect revealed in the process of the next-to-leading order fits to the data for the assymetry of polarised lepton-nucleon scattering which result in the approximate nullification of the $1/Q^2$-correction to A_1^N(x,Q^2).

LaTeX, 7 pages, 1 figure; The consideration is revised in case of multiplicatively defined twist-4 terms. Stronger constraints are obtained. 4 references added