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Related papers: Progress on neural parton distributions

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We study in details the parameterizations of the nuclear parton distributions at the next-to-next-to-leading order (NNLO) of $\alpha_s$. In low $x$ and $Q_0^2$, we observe negative gluon distribution at this order which signals the…

High Energy Physics - Phenomenology · Physics 2014-03-25 S. Atashbar Tehrani , H. Mouji

We recall the physical features of the parton distributions in the quantum statistical approach of the nucleon, which allows to describe simultaneously, unpolarized and polarized Deep Inelastic Scattering data. Some predictions from a…

High Energy Physics - Phenomenology · Physics 2015-05-27 Jacques Soffer

Optimum nuclear parton distributions are determined by an analysis of muon and electron deep inelastic scattering data. Assuming simple A dependence and polynomial functions of x and 1-x for nuclear modification of parton distributions, we…

High Energy Physics - Phenomenology · Physics 2015-06-25 M. Hirai , S. Kumano , M. Miyama

At large N_c the nucleon can be viewed as a soliton of the effective chiral lagrangian. This picture of nucleons allows a consistent nonperturbative calculation of the leading-twist parton distributions at a low normalization point. We…

High Energy Physics - Phenomenology · Physics 2009-10-28 D. Diakonov , V. Petrov , P. Pobylitsa , M. Polyakov , C. Weiss

We present recent progress on the study of the deep inelastic structure of nuclei that improves our current understanding of the mechanisms of nuclear modifications of parton distribution functions.

High Energy Physics - Phenomenology · Physics 2007-05-23 Simonetta Liuti

We present a determination of the nucleon parton distribution functions (PDFs) and of the strong coupling constant $\alpha_s$ at next-to-next-to-leading order (NNLO) in QCD based on the world data for deep-inelastic scattering and the…

High Energy Physics - Phenomenology · Physics 2012-08-08 S. Alekhin , J. Bluemlein , S. -O. Moch

Continuing with our analysis of parton distributions in the nucleon, we extend our light-front quark model in order to obtain both the helicity independent and helicity dependent parton distributions, analytically matching the results of…

High Energy Physics - Phenomenology · Physics 2017-03-08 Thomas Gutsche , Valery E. Lyubovitskij , Ivan Schmidt

The distribution of the spin of the nucleon among its constituents can be parametrized in the form of polarized parton distribution functions for quarks and gluons. Using all available data on the polarized structure function $g_1(x,Q^2)$,…

High Energy Physics - Phenomenology · Physics 2014-11-17 T. Gehrmann , W. J. Stirling

We use the recent estimates of NNLO splitting functions, made by van Neerven and Vogt, to perform exploratory fits to deep inelastic and related hard scattering data. We investigate the hierarchy of parton distributions obtained at LO, NLO…

High Energy Physics - Phenomenology · Physics 2011-09-13 A. D. Martin , R. G. Roberts , W. J. Stirling , R. S. Thorne

We review the calculation of moments of both the polarized and unpolarized parton distribution functions of the nucleon in lattice QCD, and in particular their extrapolation to the physical region. We also discuss the reconstruction of the…

High Energy Physics - Lattice · Physics 2008-11-26 W. Detmold , W. Melnitchouk , A. W. Thomas

We show that any determination of the strong coupling $\alpha_s$ from a process which depends on parton distributions, such as hadronic processes or deep-inelastic scattering, generally does not lead to a correct result unless the parton…

High Energy Physics - Phenomenology · Physics 2020-03-18 Stefano Forte , Zahari Kassabov

Polarized parton distributions and structure functions of the nucleon are analyzed in the improved valon model. The valon representation provides a model to represent hadrons in terms of quarks, providing a unified description of bound…

High Energy Physics - Phenomenology · Physics 2009-11-10 Ali N. Khorramian , A. Mirjalili , S. Atashbar Tehrani

We present parton distribution functions which include a quantitative estimate of its uncertainties. The parton distribution functions are optimized with respect to deep inelastic proton data, expressing the uncertainties as a density…

High Energy Physics - Phenomenology · Physics 2007-05-23 Walter T. Giele , Stephane A. Keller , David A. Kosower

We present a preliminary strategy for modeling multidimensional distributions through neural networks. We study the efficiency of the proposed strategy by considering as input data the two-dimensional next-to-next leading order (NNLO) jet…

High Energy Physics - Phenomenology · Physics 2017-08-02 Stefano Carrazza

We briefly discuss recent research on the spin-averaged parton densities of the proton, focusing on some aspects relevant to hard processes at the LHC. Specifically, after recalling the basic framework and the need for higher-order…

High Energy Physics - Phenomenology · Physics 2007-07-30 Andreas Vogt

Generalized parton distributions have been introduced in recent years as a suitable theoretical tool to study the structure of the nucleon. Unifying the concepts of parton distributions and hadronic form factors, they provide a…

High Energy Physics - Phenomenology · Physics 2011-09-30 Sigfrido Boffi , Barbara Pasquini

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 give a brief overview of nuclear parton distributions. First, the EMC effect is discussed together with possible interpretations such as nuclear binding and $Q^2$ rescaling. Next, we explain shadowing descriptions:…

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

We discuss the determination of polarized parton distributions from charged-current deep-inelastic scattering experiments. We summarize the next-to-leading order treatment of charged-current polarized structure functions, their relation to…

High Energy Physics - Phenomenology · Physics 2009-10-08 Stefano Forte , Michelangelo L. Mangano , Giovanni Ridolfi

We briefly review some of the developments in the study of parton distributions which have occurred since DIS2000, including discussion of uncertainties, shadowing, unintegrated and generalized distributions.

High Energy Physics - Phenomenology · Physics 2015-06-25 A. D. Martin