Fermi-Dirac distributions for quark partons

Abstract

We propose to use Fermi-Dirac distributions for quark and antiquark partons. It allows a fair description of thex-dependence of the very recent NMC data on the proton and neutron structure functionsF ^p₂ (x) andF ⁿ₂ (x) atQ ²=4 GeV², as well as the CCFR antiquark distribution$x\bar q(x)$. We show that one can also use a corresponding Bose-Einstein expression to describe consistently the gluon distribution. The Pauli exclusion principle, which has been identified to explain the flavor asymmetry of the light-quark sea of the proton, is advocated to guide us for making a simple construction of the polarized parton distributions. We predict the spin dependent structure functionsg ^p₁ (x) andg ⁿ₁ (x) in good agreement with EMC and SLAC data. The quark distributions involve some parameters whose values support well the hypothesis that the violation of the quark parton model sum rules is a consequence of the Pauli principle.