Status of the Quantum Statistical Approach to the Parton Distributions

Abstract

The role of Pauli principle advocated many years ago and the shapes of the valence and gluon parton distributions suggest to describe the parton distributios at the 𝑄 2 0 separating the non perturbative and perturbative regimes of the evolution with Fermi-Dirac functions for the quarks and a Planck formula for the gluons. In such a way their shapes are well described, the unpolarized and polarized quark distributions are given at the same time and the isospin and spin asymmetries of the nucleon sea are related to the valence distributions.