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Related papers: Polarized Parton Distributions: Theory and Experim…

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The flavor-dependent valence, sea quark and antiquark spin distributions can be determined separately from theoretical assumptions and experimental data. We have determined the valence distributions using the Bjorken sum rule and have…

High Energy Physics - Phenomenology · Physics 2014-11-17 Gordon P. Ramsey

We have extracted polarized nucleon distributions from recent data at CERN, SLAC and DESY. The flavor-dependent valence and sea quark spin distributions are determined for each experiment. The up and down distributions are comparable, but…

High Energy Physics - Phenomenology · Physics 2007-05-23 Gordon P. Ramsey , Mehrdad Goshtasbpour

In the past year, polarized deep inelastic scattering experiments at CERN and SLAC have obtained structure function measurements off proton, neutron and deuteron targets at a level of precision never before achieved. The measurements can be…

High Energy Physics - Phenomenology · Physics 2010-04-06 T. Gehrmann , W. J. Stirling

By assuming that there is no significant intrinsic polarization of the gluon, we have computed the polarized quark contributions to the proton's spin under SU(3) flavor symmetry breaking for the polarized sea and have performed a global…

High Energy Physics - Phenomenology · Physics 2009-10-28 Chung-Yi Wu

The recent high precision SMC data on polarized $\mu p$ scatterings have again confirmed that very little of the proton spin is carried by quarks. To unravel the mystery of the proton spin structure, it is quite important to know the…

High Energy Physics - Phenomenology · Physics 2009-10-28 T. Morii , S. Tanaka , T. Yamanishi

We have used recent polarized deep-inelastic scattering data from CERN and SLAC to extract information about nucleon spin structure. We find that the SMC proton data, the E142 neutron data and the deuteron data from SMC and E143 give…

High Energy Physics - Phenomenology · Physics 2009-10-28 M. Goshtasbpour , Gordon P. Ramsey

We perform a NLO analysis of polarized deep inelastic scattering data to test two different solutions to the so called spin crisis: one of them based on the axial gluon anomaly and consistent with the Bjorken sum rule and another one, where…

High Energy Physics - Phenomenology · Physics 2009-10-31 C. Bourrely , F. Buccella , O. Pisanti , P. Santorelli , J. Soffer

Considerable progress has been made in our knowledge of the spin distribution within the proton. The recently measured limits on polarized gluons in the proton suggest polarized gluons contribute very modestly to the proton spin. We will…

High Energy Physics - Phenomenology · Physics 2009-08-24 F. Myhrer

The twenty years since the announcement of the proton spin crisis by the European Muon Collaboration has seen tremendous progress in our knowledge of the distribution of spin within the proton. The problem is reviewed, beginning with the…

High Energy Physics - Phenomenology · Physics 2010-11-11 A. W. Thomas , Jefferson Lab

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

Analysis was performed of semi-inclusive and inclusive spin asymmetries determined from the polarized deep inelastic scattering by the Spin Muon Collaboration. Combined analysis of data for polarized deuterium and hydrogen targets allows…

High Energy Physics - Experiment · Physics 2007-05-23 Wojciech Wiślicki

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 present a systematic study of the proton spin structure in terms of measurable parton distributions. For a transversely-polarizedproton, we derive a polarization sum rule from the leading generalized parton distributions appearing in…

High Energy Physics - Phenomenology · Physics 2012-10-18 Xiangdong Ji , Xiaonu Xiong , Feng Yuan

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 propose new method which allows determination of the strange-sea quark spin distribution in the nucleon through measurement of various inclusive and semi-inclusive polarized deep inelastic electron- or muon-proton reactions. It is shown,…

High Energy Physics - Phenomenology · Physics 2008-11-26 L. Grigoryan

The quark and gluon structure of the proton has been under intense experimental and theoretical investigation for five decades. Even for the distributions of the well-studied valence quarks, challenges such as the value of the down quark to…

Nuclear Experiment · Physics 2019-03-27 D. F. Geesaman , P. E. Reimer

We study the available data in polarized e-p deep inelastic scattering to test two different solutions to the so called spin crisis: one of them based on the axial gluon anomaly and consistent with the Bjorken sum rule and another one,…

High Energy Physics - Phenomenology · Physics 2008-02-03 C. Bourrely , F. Buccella , O. Pisanti , P. Santorelli , J. Soffer

Within the framework of the so-called "valon" model, we argue that a substantial part of the nucleon spin, about 40%, is carried by the polarized valence quarks. The remaining is the result of cancellations between gluon polarization and…

High Energy Physics - Phenomenology · Physics 2008-11-26 Firooz Arash , Fatemeh Taghavi-Shahri

Sea quark distributions in the nucleon have naively been expected to be generated perturbatively by gluon splitting. In this case, there is no reason for the light quark and anti-quark sea distributions to be different. No asymmetries in…

High Energy Physics - Phenomenology · Physics 2015-06-25 R. Vogt

We examine the present status of the Bjorken sum rule in the light of recent data on the spin structure functions of the proton, neutron and deuteron obtained by the CERN and SLAC experimental groups. We also discuss the role of possible…

High Energy Physics - Phenomenology · Physics 2008-02-03 Philip G. Ratcliffe
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