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We extract polarized parton distribution functions (PPDFs), referred to as "KTA17," together with the highly correlated strong coupling $\alpha_s$ from recent and up-to-date $g_1$ and $g_2$ polarized structure functions world data at…

High Energy Physics - Phenomenology · Physics 2017-04-07 Hamzeh Khanpour , Sara Taheri Monfared , S. Atashbar Tehrani

Physical anomalous dimensions are a formulation of the DGLAP evolution of Deep Inelastic structure functions which is independent of factorization scheme and -scale. In this proceedings we provide an outlook on possible applications, in…

High Energy Physics - Phenomenology · Physics 2015-07-17 M. Hentschinski

New measurements are reported on the deuteron spin structure function g_1^d. These results were obtained from deep inelastic scattering of 48.3 GeV electrons on polarized deuterons in the kinematic range 0.01 < x < 0.9 and 1 < Q^2 < 40…

High Energy Physics - Experiment · Physics 2012-08-27 E155 Collaboration

We have measured the spin-dependent structure function $g_1^p$ of the proton in deep inelastic scattering of polarized muons off polarized protons, in the kinematic range $0.003<x<0.7$ and $1\,\mbox{GeV}^2<Q^2<60\,\mbox{GeV}^2$. Its first…

High Energy Physics - Phenomenology · Physics 2010-01-15 the SMC

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

High Energy Physics - Phenomenology · Physics 2009-11-07 E. Leader , A. V. Sidorov , D. B. Stamenov

We examine the behaviour of the polarised structure function data for g_1(x) in the region of small x (~0.01 to 0.1) for the various available targets (proton, neutron and deuteron) with the aim of clarifying what may be safely deduced with…

High Energy Physics - Phenomenology · Physics 2007-05-23 Mehrdad Goshtasbpour , Philip G. Ratcliffe

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

Recent results in polarized DIS are reviewed. Particular emphasis is placed on new measurements of transverse and longitudinal asymmetries, on the tests of the spin sum rules and on the analysis of the spin structure function $g_1$ in…

High Energy Physics - Phenomenology · Physics 2009-10-31 Roland Windmolders

We present an update of a phenomenological model for the spin dependent structure functions $g_1(x,Q^2)$ of the proton and neutron. This model is based on a broken SU(6) wavefunction parametrized by the unpolarized structure functions. The…

High Energy Physics - Phenomenology · Physics 2009-10-28 B. Ehrnsperger , A. Schäfer

We obtain a pair of second order differential equations in two variables $x$ and $t$ from the coupled DGLAP QCD evolution equations at small $x$ using the standard Taylor series expansion method.To that end we keep terms upto $O(x^2 )$.We…

High Energy Physics - Phenomenology · Physics 2016-12-28 Luxmi Machahari , D. K. Choudhury , P. K. Sahariah

We study how the spin-statistics theorem relates to the geometric structures on phase space that are introduced in quantisation procedures (namely a U(1) bundle and connection). The relation can be proved in both the relativistic and the…

Quantum Physics · Physics 2016-09-08 Charis Anastopoulos

We present the results of our QCD analysis for nonsinglet unpolarized quark distributions and structure function $F_2(x,Q^2)$. New parameterizations are derived for the nonsinglet quark distributions for the kinematic wide range of $x$ and…

High Energy Physics - Phenomenology · Physics 2008-12-25 Ali N. Khorramian , S. Atashbar Tehrani

We consider low-x behavior of the spin structure functions g_1(x) and h_1(x) in the unitarized chiral quark model that combines the ideas on constituent quark structure of hadrons with a geometrical scattering picture and unitarity. A…

High Energy Physics - Phenomenology · Physics 2007-05-23 Sergey Troshin , Nikolai Tyurin

We report on a high statistics quenched lattice QCD calculation of the deep-inelastic structure functions $F_1$, $F_2$, $g_1$ and $g_2$ of the proton and neutron. The theoretical basis for the calculation is the operator product expansion.…

High Energy Physics - Lattice · Physics 2008-11-26 M. Göckeler , R. Horsley , E. -M. Ilgenfritz , H. Perlt , P. Rakow , G. Schierholz , A. Schiller

First results of a non--singlet QCD analysis of the structure function $F_2(x,Q^2)$ in 3--loop order based on the non--singlet world data are presented. Correlated errors are determined and their propagation through the evolution equations…

High Energy Physics - Phenomenology · Physics 2009-11-10 J. Blümlein , H. Böttcher , A. Guffanti

The nuclear effects in the spin-dependent structure functions $g_1^D$ and $b_2^D$ are calculated in the relativistic approach based on the Bethe-Salpeter equation with a realistic meson-exchange potential. The results of calculations are…

High Energy Physics - Phenomenology · Physics 2015-06-25 A. Yu. Umnikov , L. P. Kaptari , K. Yu. Kazakov , F. C. Khanna

Inspired by recent measurements with the CLAS detector at Jefferson Lab, we perform a self-consistent analysis of world data on the proton structure function g1 in the range 0.17 < Q2 < 30 (GeV/c)**2. We compute for the first time low-order…

High Energy Physics - Phenomenology · Physics 2008-11-26 M. Osipenko , S. Simula , W. Melnitchouk , P. Bosted , V. Burkert , E. Christy , K. Griffioen , C. Keppel , S. Kuhn , G. Ricco

We study deep-inelastic scattering from polarized nuclei within a covariant framework. A clear connection is established between relativistic and non-relativistic limits, which enables a rigorous derivation of convolution formulae for the…

High Energy Physics - Phenomenology · Physics 2009-09-25 S. A. Kulagin , W. Melnitchouk , G. Piller , W. Weise

Predictions for g_1(x,Q^2) at low Q^2 are obtained in the framework of the GVMD model. Contributions from both light and heavy vector mesons are evaluated. The DHGHY sum rule is employed to fix the magnitude of the light vector meson…

High Energy Physics - Phenomenology · Physics 2007-05-23 Barbara Badełek , Jan Kwieciński , Beata Ziaja

We show that it is possible to use hard-Pomeron behavior to the gluon distribution and singlet structure function at low $x$. We derive a second-order independent differential equation for the gluon distribution and the singlet structure…

High Energy Physics - Phenomenology · Physics 2014-02-05 B. Rezaei , G. R. Boroun