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Related papers: The Small-x Behaviour of the Singlet Polarized Str…

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Theoretical predictions for polarized nucleon structure function $g_1(x,Q^2)$ at low $Q^2$ are obtained in the framework of the Generalized Vector Meson Dominance model. Contributions from both light and heavy vector mesons are evaluated.…

High Energy Physics - Phenomenology · Physics 2011-09-13 Barbara Badełek , Jan Kwieciński , Beata Ziaja

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

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

The small-$x$ contributions to the Bjorken sum rule within unified picture $ln^2x+$LO DGLAP for different input parametrisations $g_1^{NS}(x,Q_0^2)$ are presented. Theoretical predictions for $\int_{0}^{0.003} g_1^{NS}(x,Q^2=10) dx$ are…

High Energy Physics - Phenomenology · Physics 2014-11-18 D. Kotlorz , A. Kotlorz

A next-to-leading order QCD calculation of non-singlet spin structure function, $g_{1}^{NS} $ is presented within the valon representation of Hadrons. In the valon model, it is assumed that a nucleon is composed of three dressed valence…

High Energy Physics - Phenomenology · Physics 2014-11-21 Fatemeh Taghavi Shahri , Firooz Arash

The Standard Approach (SA) for description of the structure function g_1 combines the DGLAP evolution equations and Standard Fits for the initial parton densities. The DGLAP equations describe the region of large Q^2 and large x, so there…

High Energy Physics - Phenomenology · Physics 2007-07-13 B. I. Ermolaev , M. Greco , S. I. Troyan

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

The longitudinal structure function in deep inelastic scattering is one of the observables from which the gluon distribution can be unfolded. Consequently, this observable can be used to constrain the QCD dynamics at small $x$. In this work…

High Energy Physics - Phenomenology · Physics 2011-09-13 V. P. Goncalves , M. V. T. Machado

A unified equation for the non-singlet spin dependent structure function $g_1^{ns}(x,Q^2)$ which incorporates the complete leading order Altarelli-Parisi evolution at finite $x$ and double logarithmic $ ln^2(1/x)$ effects at $x \to 0$ is…

High Energy Physics - Phenomenology · Physics 2014-11-17 B. Badełek , J. Kwieciński

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

We construct small-x evolution equations which can be used to calculate quark and anti-quark helicity TMDs and PDFs, along with the $g_1$ structure function. These evolution equations resum powers of $\alpha_s \, \ln^2 (1/x)$ in the…

High Energy Physics - Phenomenology · Physics 2016-07-15 Yuri V. Kovchegov , Daniel Pitonyak , Matthew D. Sievert

The $\rho$ meson polarized generalized parton distribution functions, its structure functions $g_1$ and $g_2$ and its axial form factors ${\tilde G}_{1,2}$ are studied based on a light-front quark model for the first time. Comparing our…

High Energy Physics - Phenomenology · Physics 2019-02-06 Bao-Dong Sun , Yu-Bing Dong

The twist--2 contributions to the polarized structure functions in deep inelastic lepton--hadron scattering are calculated including the exchange of weak bosons and using both the operator product expansion and the covariant parton model. A…

High Energy Physics - Phenomenology · Physics 2007-05-23 J. Blümlein , N. Kochelev

We generalize the Bartels-Ermolaev-Ryskin approach for the $g_1$ structure function at small-$x$ to determine the small-$x$ asymptotic behavior of the orbital angular momentum distributions in QCD. We present an exact analytical solution of…

High Energy Physics - Phenomenology · Physics 2019-09-04 Renaud Boussarie , Yoshitaka Hatta , Feng Yuan

We present a phenomenological study of the small-x behaviour of gluon distribution function $G(x,Q^2)$ at next-to-leading order (NLO) and next-to-next-to-leading order(NNLO) in light of the nonlinear Gribov-Ryskin-Levin-Mueller-Qiu…

High Energy Physics - Phenomenology · Physics 2019-01-23 M. Lalung , P. Phukan , J. K. Sarma

We show that if the Lorentz transformation properties of diffraction are other than scalar, the $x \rightarrow 0$ behaviour of $g_1(x,Q^2)$ can grow. We compare with new data on $g_1^p$ from SMC, assess implications for sum rules and for…

High Energy Physics - Phenomenology · Physics 2009-10-28 F. E. Close , R. G. Roberts

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

An estimation of the higher twist contribution to the polarized nonsinglet structure function $g_1$ is given. Its first moment is generally assumed to be small but this could be due to a cancellation of its contribution in different…

High Energy Physics - Phenomenology · Physics 2009-10-28 M. Meyer-Hermann , M. Maul , L. Mankiewicz , E. Stein , A. Schäfer

The importance of polarised gluons fragmenting into $\Lambda$ in the polarised $e^+ e^-$ annihilation is discussed using the Altarelli-Parisi evolution equations satisfied by the quark and gluon fragmentation functions. In this context, the…

High Energy Physics - Phenomenology · Physics 2014-11-17 V. Ravindran

The conventional and linearly polarized Weizs\"acker-Williams gluon distributions at small x are defined from the two-point function of the gluon field in light-cone gauge. They appear in the cross section for dijet production in deep…

High Energy Physics - Phenomenology · Physics 2018-03-14 Adrian Dumitru , Vladimir Skokov

We prove that regulating infrared divergencies generates power (~1/(Q^2)^k) corrections to the spin structure function g_1 at small x and large Q^2. At the same time it leads to the corrections ~(Q^2)^k at small Q^2. We present the explicit…

High Energy Physics - Phenomenology · Physics 2010-03-25 B. I. Ermolaev , M. Greco , S. I. Troyan