Parton Distribution Functions properties of the statistical model

Abstract

We show that the parton distribution functions (PDF) described by the statistical model have very interesting physical properties which help to understand the structure of partons. The role of the quark helicity components is emphasized as they represent the building blocks of the PDF. In the model the sign of the polarized quarks PDF comes out in a quite natural way once the thermodynamical potentials with a given helicity are known. Introducing the concept of entropy we study the states madeof |2u + d >, |u +d +s > and $|2\bar{u}+\bar{d}>$, for a fixed Q^2, the variation with x shows that the first state has a dominant entropy due to the effect of u quark. We prove that the PDF parameters obtained from experiments give in fact an optimal solution of an entropy equation subject to constraints. We develop a new approach of the polarized gluon density based on a neural model which explains its property, in particular, a large positivity value and an agreement with the positvity constraint. An extension of this neural approach is applied to quarks giving a coherent description of the partons structure.

22 pages, 19 figures, new results added

References in corpus (6)

• New parton distribution functions from a global analysis of quantum chromodynamics
• A first unbiased global determination of polarized PDFs and their uncertainties
• Evidence for polarization of gluons in the proton
• New developments in the statistical approach of parton distributions: tests and predictions up to LHC energies
• Exploring central opacity and asymptotic scenarios in elastic hadron scattering
• Statistical description of the proton spin with a large gluon helicity distribution

Cited by in corpus (2)

• Exploring central opacity and asymptotic scenarios in elastic hadron scattering
• Properties of structure functions from helicity components\\ of light quarks and antiquarks in the statistical model