Constraints on nonsinglet polarized parton densities from the infrared-renormalon model

Using the infrared-renormalon approach, we obtain the constraints on the next-to-leading order nonsinglet polarized parton densities. The advocated feature follows from the consideration of the effect revealed in the rocess of the next-to-leading order fits to the data for the asymmetry of polarized lepton-nucleon scattering, which result in the approximate nullification of the 1/Q²-correction to A ₁ ^N (x, Q²).