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We make a critical study of the relationship between the singlet structure function $F_{2}^{S}$ and the gluon distribution $G(x,Q^{2})$ proposed in the past two decades, which is frequently used to extract the gluon distribution from the…

High Energy Physics - Phenomenology · Physics 2014-04-22 G. R. Boroun

We have examined the spin structure of the proton in the region of the nucleon resonances (1.085 GeV < W < 1.910 GeV) at an average four momentum transfer of Q^2 = 1.3 GeV^2. Using the Jefferson Lab polarized electron beam, a spectrometer,…

We present the results of our QCD analysis for non-singlet unpolarized quark distributions and structure function $F_2(x,Q^2)$ up to N$^3$LO. In this regards 4-loop anomalous dimension can be obtain from the Pad\'e approximations. The…

High Energy Physics - Phenomenology · Physics 2010-02-03 Ali N. Khorramian , H. Khanpour , S. Atashbar Tehrani

We construct a simple two-phase model of the nucleon structure functions valid for both small and large Q^2 and in the broad range of Bjorken x. The model incorporates hadron dominance at small x and Q^2 and parton model at large Q^2. The…

High Energy Physics - Phenomenology · Physics 2015-06-25 A. Szczurek , V. Uleshchenko

We present a Next-to-Leading order perturbative QCD analysis of world data on the spin dependent structure functions $g_1^p, g_1^n$, and $g_1^d$, including the new experimental information on the $Q^2$ dependence of $g_1^n$. Careful…

High Energy Physics - Phenomenology · Physics 2008-11-26 The SLAC E154 Collaboration , K. Abe

Two spin-dependent structure functions $\hat g_1$ and $\hat g_2$ for the inclusive spin-half baryon production in electron-positron annihilation are studied in the context of QCD factorization as well as in the naive quark parton model. As…

High Energy Physics - Phenomenology · Physics 2009-10-28 Wei Lu , Xue Qian Li , Haiming Hu

The resummation of $O(\alpha^{l+1} \ln^{2l} x)$ terms in the evolution kernels of non--singlet combinations of structure functions is investigated for both QED abd QCD. Numerical results are presented for unpolarized and polarized structure…

High Energy Physics - Phenomenology · Physics 2007-05-23 J. Blümlein , A. Vogt

We start from an MIT-bag model calculation which provides information about the constituent quark distributions in the nucleon. The constituent quarks, however, are themselves considered as complex objects whose partonic substructure is…

High Energy Physics - Phenomenology · Physics 2009-09-25 J. Keppler , H. M. Hofmann

We investigate the effect of the structure function F_L in global parton analyses of deep inelastic and related hard scattering data. We perform NLO and NNLO analyses which include the reduced cross section HERA data at high y, as well as…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. D. Martin , W. J. Stirling , R. S. Thorne

We have measured the spin-dependent structure function $g_1^p$ in inclusive deep-inelastic scattering of polarized muons off polarized protons, in the kinematic range $0.003 < x < 0.7$ and $1 GeV^2 < Q^2 < 60 GeV^2$. A next-to-leading order…

High Energy Physics - Experiment · Physics 2010-01-15 D. Adams

We review the nucleon's polarized structure functions from the viewpoint of gauge invariant, nonlocal light-cone operators in QCD. We discuss a systematic treatment of the polarized structure functions and the corresponding parton…

High Energy Physics - Phenomenology · Physics 2017-08-23 J. Kodaira

We present a set of formulae to extract the gluon distribution function from the deep inelastic structure function F$_2$ and its derivative dF$_2$/dlnQ$^2$ at small x in the leading and next-to-leading order of perturbation theory. The…

High Energy Physics - Phenomenology · Physics 2009-10-28 A. V. Kotikov , G. Parente

A simple model for nuclear structure functions in the region of small $x$ and small and moderate $Q^2$, is presented. It is a parameter-free extension, in the Glauber-Gribov approach to nuclear collisions, of a saturation model for the…

High Energy Physics - Phenomenology · Physics 2007-05-23 N. Armesto

Quark-hadron duality is studied in a systematic way for both the unpolarized and polarized structure functions, by taking into account all the available data in the resonance region.In both cases, a detailed perturbative QCD based analysis…

High Energy Physics - Phenomenology · Physics 2009-11-11 A. Fantoni , N. Bianchi , S. Liuti

A next-to-leading order (NLO) QCD analysis of the spin-dependent parton distributions $\Delta f^{\gamma}(x,Q^2)$ of the longitudinally polarized photon and of its structure function $g_1^{\gamma}(x,Q^2)$ is performed within the framework of…

High Energy Physics - Phenomenology · Physics 2008-11-26 M. Stratmann , W. Vogelsang

We investigate polarized deuteron structure functions at small values of the Bjorken variable, x < 0.1. In this region contributions from the coherent interaction of diffractively excited hadronic states with both nucleons become important.…

High Energy Physics - Phenomenology · Physics 2008-11-26 J. Edelmann , G. Piller , W. Weise

The explicit expressions for the non-singlet and singlet components of the DIS structure function g_1 comprising the DGLAP -expressions for the coefficient functions and the anomalous dimensions, and accounting for the total resummation of…

High Energy Physics - Phenomenology · Physics 2017-08-23 B. I. Ermolaev , M. Greco , S. I. Troyan

We review the nucleon's twist-3 polarized structure functions from the viewpoint of gauge invariant, nonlocal light-cone operators in QCD. We discuss a systematic treatment of the polarized structure functions and the corresponding parton…

High Energy Physics - Phenomenology · Physics 2009-10-31 Jiro Kodaira , Kazuhiro Tanaka

We will give an outline of the computation of the QCD corrections to the spin structure function g_1(x,Q^2) and the spin fragmentation function g_1^H(x,Q^2) which are measured in deep inelastic electron-proton scattering and in…

High Energy Physics - Phenomenology · Physics 2007-05-23 W. L. van Neerven

The higher twist corrections $h^N(x)/Q^2$ to the spin dependent proton and neutron $g_1$ structure functions are extracted from the world data on $g_1(x,Q^2)$ in a model independent way and found to be non-negligible. Their role in…

High Energy Physics - Phenomenology · Physics 2007-05-23 E. Leader , A. V. Sidorov , D. B. Stamenov