An analysis of elastic scattering reactions with a Fermi-Dirac pomeron opaqueness in impact parameter space

In the Bourrely-Soffer-Wu model (BSW) we introduce for the pomeron a new opaqueness in impact parameter space in terms of different quark contributions described by a Fermi-Dirac distribution. In order to check the validity of this assumption we consider $p~p$, $\bar p~p$, and $\pi^{\pm}~p$ elastic scattering. We emphasize the role of the gluon above the diffraction peak in the differential cross sections. Once these contributions are determined we extend the model to light nuclei elastic reactions like $p~d$, p~^4\mbox{He} and \pi^{\pm}~^4\mbox{He}. The results obtained show a good description of all these elastic processes over the available experimental energy range and moderate momentum transfer.Comment: 29 pages 25 figure

Statistical description of the proton spin with a large gluon helicity distribution

The quantum statistical parton distributions approach proposed more than one decade ago is revisited by considering a larger set of recent and accurate Deep Inelastic Scattering (DIS) experimental results. It enables us to improve the description of the data by means of a new determination of the parton distributions. We will see that a large gluon polarization emerges, giving a significant contribution to the proton spin.Comment: 11 pages, 4 figure

New Statistical PDFs: Predictions and Tests up to LHC Energies

The quantum statistical parton distributions approach proposed more than one decade ago is revisited by considering a larger set of recent and accurate Deep Inelastic Scattering experimental results. It enables us to improve the description of the data by means of a new determination of the parton distributions. This global next-to-leading order QCD analysis leads to a good description of several structure functions, involving unpolarized parton distributions and helicity distributions, in a broad range of $x$ and $Q^2$ and in terms of a rather small number of free parameters. There are several challenging issues, in particular the behavior of $\bar d(x) / \bar u(x)$ at large $x$, a possible large positive gluon helicity distribution, etc.. The predictions of this theoretical approach will be tested for single-jet production and charge asymmetry in $W^{\pm}$ production in $\bar p p$ and $p p$ collisions up to LHC energies, using recent data and also for forthcoming experimental results.Comment: 4 pages, 3 figures, Invited talk at Diffraction 2016, Acireale, Sicily (Italy), Sept. 2 - 8 (2016), to be published in the AIP Conference Proceedings. arXiv admin note: substantial text overlap with arXiv:1510.0618

Statistical Polarized Parton Distributions at Large-x

6 pages, 3figuresWe present a new set of polarized parton distributions constructed in a statistical physical picture of the nucleon. The chiral peoperties of QCD lead to precise relations between quarks and antiquarks distributions and the importance of the Pauli exclusion principle is also emphasized. The model involves a small number of free parameters which are determined by a global next-to-leading order QCD analysis of unpolarized and polarized deep-inelastic scattering data. We discuss the implications of experimental data on the structure of polarized distributions