Eur. Phys. J. C 23, 487-501 (2002)
https://doi.org/10.1007/s100520100855

A statistical approach for polarized parton distributions

¹ Centre de Physique Théorique, CNRS-Luminy Case 907, 13288 Marseille Cedex 9, France
² Dipartimento di Scienze Fisiche, Università di Napoli, Via Cintia, 80126 Napoli, Italy

Received: 19 September 2001
Published online: 8 March 2002

Abstract

A global next-to-leading order QCD analysis of unpolarized and polarized deep-inelastic scattering data is performed with parton distributions constructed in a statistical physical picture of the nucleon. The chiral properties of QCD lead to strong relations between quarks and antiquarks distributions and the importance of the Pauli exclusion principle is also emphasized. We obtain a good description, in a broad range of x and Q², of all measured structure functions in terms of very few free parameters. We stress the fact that at RHIC-BNL the ratio of the unpolarized cross sections for the production of W⁺ and W^- in pp collisions will directly probe the behavior of the d(x)/ u(x) ratio for x ≥ 0.2, a definite and important test for the statistical model. Finally, we give specific predictions for various helicity asymmetries for the W^±, Z production in pp collisions at high energies, which will be measured with forthcoming experiments at RHIC-BNL and which are sensitive tests of the statistical model for Δu(x) and Δd(x).