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Related papers: Polarized Partons at Next-to-Leading Order

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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

A next-to-leading order QCD analysis of spin asymmetries and structure functions in polarized deep inelastic lepton nucleon scattering is presented within the framework of the radiative parton model. A consistent NLO formulation of the…

High Energy Physics - Phenomenology · Physics 2009-10-28 M. Gluck , E. Reya , M. Stratmann , W. Vogelsang

In many calculations involving polarized twist-2 parton densities to higher order in the strong coupling constant one uses the Larin scheme to describe chiral effects in dimensional regularization. Upon forming observables, the scheme…

High Energy Physics - Phenomenology · Physics 2024-05-28 J. Blümlein , M. Saragnese

We study parametrization of polarized parton distribution functions in the \alpha_s leading order (LO) and in the next-to-leading order (NLO). From \chi^2 fitting to the experimental data on A_1, optimum polarized distribution functions are…

High Energy Physics - Phenomenology · Physics 2009-10-31 M. Hirai , H. Kobayashi , M. Miyama

We calculated the polarized parton distributions in leading order approximation in QCD from valon model. Polarized structure function of the nucleon are analyzed in the polarized valon model in which a nucleon is assumed to be a bound state…

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

Reliable knowledge of parton distributions at large x is crucial for many searches for new physics signals in the next generation of collider experiments. Although these are generally well determined in the small and medium x range, it has…

High Energy Physics - Phenomenology · Physics 2009-10-31 S. Kuhlmann , J. Huston , J. Morfin , F. Olness , J. Pumplin , J. F. Owens , W. K. Tung , J. J. Whitmore

We present a first QCD analysis of next-to-next-leading-order (NNLO) contributions of the spin-dependent parton distribution functions (PPDFs) in the nucleon and their uncertainties using the Jacobi polynomial approach. Having the NNLO…

High Energy Physics - Phenomenology · Physics 2016-06-24 F. Taghavi Shahri , Hamzeh Khanpour , S. Atashbar Tehrani , Z. Alizadeh Yazdi

Reliable knowledge of parton distributions at large x is crucial for many searches for new physics signals in the next generation of collider experiments. Although these are generally well determined in the small and medium x range, it has…

High Energy Physics - Phenomenology · Physics 2007-05-23 S. Kuhlmann , J. Huston , J. Morfin , F. Olness , J. Pumplin , J. F. Owens , W. K. Tung , J. J. Whitmore

We report the polarized parton distributions proposed by the Asymmetry Analysis Collaboration (AAC). Using parametrized distributions at Q^2=1 GeV^2 and measured A_1 data, we determine optimum polarized distributions in the leading order…

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

The results of a next-to-leading order calculation of heavy quark production in longitudinally polarized photon-nucleon collisions are presented. At c.m. energy $\sqrt{S}=10$ GeV, for $\vec \gamma +\vec p \to c+X$, cross sections…

High Energy Physics - Phenomenology · Physics 2009-10-31 A. P. Contogouris , Z. Merebashvili , G. Grispos

The hard-gluonic contribution to the first moment of the polarized proton structure function $g_1^p(x)$ is dependent of the factorization convention chosen in defining the quark spin density and the hard cross section for photon-gluon…

High Energy Physics - Phenomenology · Physics 2009-10-28 Hai-Yang Cheng , Hung Hsiang Liu , Chung-Yi Wu

We give an overview of the current status of investigations of the polarization of gluons in the nucleon. We describe some of the physics of the spin-dependent gluon parton distribution and its phenomenology in high-energy polarized…

High Energy Physics - Phenomenology · Physics 2008-11-26 Marco Stratmann , Werner Vogelsang

We review the present status of polarized structure functions measured in deep-inelastic scattering. We discuss the x and Q^2 dependence of the structure function g_1, and how it can be used to test perturbative QCD at next-to-leading order…

High Energy Physics - Phenomenology · Physics 2008-02-03 Stefano Forte

We recall the physical features of the parton distributions in the quantum statistical approach of the nucleon. Some predictions from a next-to-leading order QCD analysis are compared to recent experimental results. We also consider their…

High Energy Physics - Phenomenology · Physics 2011-07-26 Jacques Soffer

We perform a global leading-order QCD fit to recent polarized structure function data in order to extract a consistent set of spin-dependent parton distributions. Assuming that there is no significant intrinsic polarization of the quark…

High Energy Physics - Phenomenology · Physics 2007-05-23 T. Gehrmann , W. J. Stirling

We investigate spin-dependent parton distributions in the polarized virtual photon target in perturbative 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…

High Energy Physics - Phenomenology · Physics 2009-01-07 Ken Sasaki , Tsuneo Uematsu

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

The need for accurate and precise polarised parton distribution functions (PDFs) is becoming increasingly crucial in view of the Electron-Ion Collider experimental program foreseen in the coming years. Two global PDF determinations at…

High Energy Physics - Phenomenology · Physics 2024-09-17 Amedeo Chiefa

We report global analysis results for polarized parton distribution functions in the nucleon. The optimum distributions are determined by using spin asymmetry data on polarized lepton scattering on proton, neutron, and deuteron. Their…

High Energy Physics - Phenomenology · Physics 2009-11-11 M. Hirai , S. Kumano , N. Saito

Collider data can play an important role in determining the parton distribution functions of the nucleon. I present a formalism which makes it possible to use next-to-leading order calculations in such a determination, while minimizing the…

High Energy Physics - Phenomenology · Physics 2009-10-30 David A. Kosower