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We have made next to leading order QCD fit to the deep inelastic spin asymmetries on nucleons and we determined polarised quark and gluon densities. The functional form for such distributions was inspired by the Martin, Roberts and Stirling…

High Energy Physics - Phenomenology · Physics 2007-05-23 Stanislaw Tatur , Jan Bartelski , Miroslaw Kurzela

This talks examines the effect of angular ordering on the small-x evolution of the unintegrated gluon distribution, and discusses the characteristic function for the CCFM equation.

High Energy Physics - Phenomenology · Physics 2016-11-03 M. Scorletti

We introduce a variational wave-function to study the polaron formation when the electronic transfer integral depends on the relative displacement between nearest-neighbor sites giving rise to a non-local electron-phonon coupling with…

Strongly Correlated Electrons · Physics 2009-11-10 C. A. Perroni , E. Piegari , M. Capone , V. Cataudella

A phenomenological parameterization of the proton polarized structure function has been developed for x > 0.02 using deep inelastic data up to ~ 50 (GeV/c)**2 as well as available experimental results on both photo- and electro-production…

High Energy Physics - Phenomenology · Physics 2009-11-07 S. Simula , M. Osipenko , G. Ricco , M. Taiuti

We report the polarized parton distributions proposed by the Asymmetry Analysis Collaboration (AAC). Using parametrized distributions at Q^2=1 GeV^2 and measured A_1 data, we determine optimum polarized distributions in the leading order…

High Energy Physics - Phenomenology · Physics 2007-05-23 S. Kumano

It is shown that the previously noted extreme perturbative instability of the longitudinal structure function F_L(x,Q^2) in the small Bjorken-$x$ region, is a mere artefact of the commonly utilized `standard' gluon distributions. In…

High Energy Physics - Phenomenology · Physics 2009-11-13 Cristian Pisano

We investigate the nucleon and pion gluon distribution functions in the framework of holographic QCD, focusing on the small Bjorken x region. Based on an approximate relation, the gluon distributions are extracted from structure functions…

High Energy Physics - Phenomenology · Physics 2020-06-24 Akira Watanabe , Takahiro Sawada , Mei Huang

Spin-dependent parton distributions in the polarized virtual photon are investigated in QCD up to the next-to-leading order (NLO). In the case $\Lambda^2 \ll P^2 \ll Q^2$, where $-Q^2$ ($-P^2$) is the mass squared of the probe (target)…

High Energy Physics - Phenomenology · Physics 2009-10-31 Ken Sasaki , Tsuneo Uematsu

We present a Monte Carlo based analysis of the combined world data on polarized lepton-nucleon deep-inelastic scattering at small Bjorken $x$ within the polarized quark dipole formalism. We show for the first time that double-spin…

High Energy Physics - Phenomenology · Physics 2021-08-11 Daniel Adamiak , Yuri V. Kovchegov , W. Melnitchouk , Daniel Pitonyak , Nobuo Sato , Matthew D. Sievert

This talks examines the effect of angular ordering on the small-x evolution of the unintegrated gluon distribution, and discusses the characteristic function for the CCFM equation.

High Energy Physics - Phenomenology · Physics 2007-05-23 M. Scorletti

Nucleon resonance contributions to the polarized proton $g_1$ and $g_2$ structure functions are computed from resonance electroexcitation amplitudes extracted from CLAS exclusive meson electroproduction data. Including resonances in the…

High Energy Physics - Phenomenology · Physics 2023-03-21 A. N. Hiller Blin , V. I. Mokeev , W. Melnitchouk

In recent papers, we have established the existence of gauge-invariant decomposition of nucleon spin, each term of which can be related to known high-energy deep-inelastic-scattering observables. A subtlety remains, however, for the…

High Energy Physics - Phenomenology · Physics 2011-08-12 Masashi Wakamatsu

Structure functions of polarized spin-1 hadrons will be measured at various accelerator facilities in the near future. Recently, transverse-momentum-dependent and collinear parton distribution functions were theoretically proposed at twist…

High Energy Physics - Phenomenology · Physics 2022-01-27 S. Kumano , Qin-Tao Song

We recall our recent description of quark parton densities of the proton at $Q^2=4 GeV^2$ in terms of Fermi-Dirac distributions parametrized with very few free parameters. We have also proposed some simple assumptions to relate unpolarized…

High Energy Physics - Phenomenology · Physics 2016-09-01 Claude Bourrely , Jacques Soffer

We discuss the impact of recent high-statistics RHIC data on the determination of the gluon polarization in the proton in the context of a global QCD analysis of polarized parton distributions. We find clear evidence for a non-vanishing…

High Energy Physics - Phenomenology · Physics 2014-07-09 Daniel de Florian , Rodolfo Sassot , Marco Stratmann , Werner Vogelsang

We present a set of independent formulae to extract the gluon distribution and singlet structure function from its derivatives with respect to $lnQ^{2}$ in the next- to- leading order of perturbation theory at low-$x$ based on a hard…

High Energy Physics - Phenomenology · Physics 2016-11-15 G. R. Boroun

This article is an introduction to parton distribution functions and their generalizations which describe the quark and gluon structure of hadrons, and can be measured in various high-energy scattering processes. We provide the theoretical…

High Energy Physics - Phenomenology · Physics 2026-01-23 Cédric Lorcé , A. Metz , B. Pasquini , P. Schweitzer

We present a systematic study of the proton spin structure in terms of measurable parton distributions. For a transversely-polarizedproton, we derive a polarization sum rule from the leading generalized parton distributions appearing in…

High Energy Physics - Phenomenology · Physics 2012-10-18 Xiangdong Ji , Xiaonu Xiong , Feng Yuan

Using a perturbative model for diffractive interactions, we derive an expression for the polarized diffractive structure function $g_1^D$ in the high energy limit. This structure function is given by the interference of diffractive…

High Energy Physics - Phenomenology · Physics 2011-09-13 J. Bartels , T. Gehrmann , M. G. Ryskin

We calculated the polarized parton distributions in leading order approximation in QCD from valon model. Polarized structure function of the nucleon are analyzed in the polarized valon model in which a nucleon is assumed to be a bound state…

High Energy Physics - Phenomenology · Physics 2007-05-23 S. Atashbar Tehrani , Ali N. Khorramian