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The flavor-dependent valence, sea quark and antiquark spin distributions can be determined separately from theoretical assumptions and experimental data. We have determined the valence distributions using the Bjorken sum rule and have…

High Energy Physics - Phenomenology · Physics 2014-11-17 Gordon P. Ramsey

An algebraic Ansatz for the proton's Poincar\'e-covariant wave function, which includes both scalar and pseudovector diquark correlations, is used to calculate proton valence, sea, and glue distribution functions (DFs). Regarding…

High Energy Physics - Phenomenology · Physics 2022-04-20 Lei Chang , Fei Gao , Craig D. Roberts

Using constituent quark model constraints we calculate the gluon and sea content of pions solely in terms of their valence density and the known sea and gluon densities of the nucleon. The resulting small-x predictions for g^{pi}(x,Q^2) and…

High Energy Physics - Phenomenology · Physics 2011-09-13 M. Gluck , E. Reya , M. Stratmann

We study the evolution of parton distributions down to low scales by considering several of their Mellin moments. For the initial conditions, we use a broad array of current parton density fits. Confirming earlier findings in the…

High Energy Physics - Phenomenology · Physics 2020-01-08 Markus Diehl , Pascal Stienemeier

In this paper polarized valon distribution is derived from unpolarized valon distribution. In driving polarized valon distribution some unknown parameters exist which must be determined by fitting to experimental data. Here we have used…

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

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

We calculate the spin density matrix of the hadron $h$ created via quark fragmentation in the process $e^-e^+ \to q\bar q \to h + X$. In the case of $h=\Lambda$ the experimental data could possibly elucidate the problem of $s$-quark…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. Anselm , M. Anselmino , F. Murgia , M. G. Ryskin

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…

High Energy Physics - Phenomenology · Physics 2015-06-22 Claude Bourrely , Jacques Soffer

In the high energy regime, the proton structure consists of a very large number of particles called partons (quarks and gluons) that interact with each other, according to the theory of strong interactions, Quantum Chromodynamics (QCD).…

High Energy Physics - Phenomenology · Physics 2018-08-06 Gilvana C. Penedo , Werner K. Sauter

The high density parton effects are strongly dependent of the spatial gluon distribution within the proton, with radius $R$, which cannot be derived from perturbative QCD. In this paper we assume that the unitarity corrections are present…

High Energy Physics - Phenomenology · Physics 2009-10-31 M. B. Gay Ducati , Victor Goncalves

In the Framework of {\it{valon model}} we have calculated the parton distribution in a valon for both the polarized and unpolarized cases. These distributions are originated purely from the dressing of a valence quark in QCD and are common…

High Energy Physics - Phenomenology · Physics 2007-05-23 Firooz Arash , Fatemeh Taghavi

Taking proton as an ensemble of quark-gluon Fock states and using the principle of detailed balance, we construct a simple statistical model for parton distribution of proton. The recent observed Bjorken-$x$ dependent light flavor sea quark…

High Energy Physics - Phenomenology · Physics 2009-11-07 Yong-Jun Zhang , Bing-Song Zou , Li-Ming Yang

Generalized parton distributions (GPDs) are studied at the hadronic (nonperturbative) scale within different assumptions based on a relativistic constituent quark model. In particular, by means of a meson-cloud model we investigate the role…

High Energy Physics - Phenomenology · Physics 2009-11-10 B. Pasquini , M. Traini , S. Boffi

Based on quantum fluctuations in momentum and of the proton into meson-baryon pairs, we develop a physical model for the non-perturbative x-shape of parton density functions in the proton. The model describes the proton structure function…

High Energy Physics - Phenomenology · Physics 2007-05-23 Johan Alwall , Gunnar Ingelman

The lowest two Mellin moments of hadronic Generalized Parton Distributions are explored within a model that allows investigation of the inter-related quark and gluon contributions. For light quarks their dynamical connection is strong due…

High Energy Physics - Phenomenology · Physics 2023-06-14 Peter C. Tandy

Dynamical parton densities, generated radiatively from valence-like inputs at some low resolution scale, are confronted with recent small-x data on deep inelastic and other hard scattering processes. It is shown that within theoretical…

High Energy Physics - Phenomenology · Physics 2011-09-13 M. Gl"uck , E. Reya , A. Vogt

In the past year, polarized deep inelastic scattering experiments at CERN and SLAC have obtained structure function measurements off proton, neutron and deuteron targets at a level of precision never before achieved. The measurements can be…

High Energy Physics - Phenomenology · Physics 2010-04-06 T. Gehrmann , W. J. Stirling

Generalized parton distributions (GPDs) are studied at the hadronic (nonperturbative) scale within different assumptions based on a relativistic constituent quark model. In particular, by means of a meson-cloud model we investigate the role…

High Energy Physics - Phenomenology · Physics 2009-11-11 S. Boffi , B. Pasquini , M. Traini

This paper contains three parts relating to the nucleon spin structure in a simple picture of the nucleon: (i) The polarized gluon distribution in the proton is dynamically predicted starting from a low scale by using a nonlinear QCD…

High Energy Physics - Phenomenology · Physics 2015-10-14 Wei Zhu , Jianhong Ruan

We present pion and kaon parton distribution functions from a global QCD analysis of the experimental data within the framework of dynamical parton model. We use the DGLAP equations with parton-parton recombination corrections and the…

High Energy Physics - Phenomenology · Physics 2021-06-03 Chengdong Han , Gang Xie , Rong Wang , Xurong Chen