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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 discuss the spin structure of the proton in a light-cone treatment of the chiral quark model. Based on the fact that the quark helicity ($\Delta q$) measured in polarized deep inelastic scattering experiments is actually the quark spin…

High Energy Physics - Phenomenology · Physics 2012-07-03 Xinyu Zhang , Bo-Qiang Ma

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

A review on the theoretical aspects and the experimental results of polarized deep inelastic scattering and of other hard scattering processes is presented. The following items are discussed: longitudinally polarized structure functions,…

High Energy Physics - Phenomenology · Physics 2011-01-25 Bodo Lampe , Ewald Reya

We report on a precision measurement of the neutron spin structure function $g^n_1$ using deep inelastic scattering of polarized electrons by polarized ^3He. For the kinematic range 0.014<x<0.7 and 1 (GeV/c)^2< Q^2< 17 (GeV/c)^2, we obtain…

High Energy Physics - Experiment · Physics 2012-08-03 The SLAC E154 Collaboration , K. Abe

We investigate an asymmetry in the angular distribution of hard elastic proton-neutron scattering with respect to 90deg center of mass scattering angle. We demonstrate that the magnitude of the angular asymmetry is related to the…

High Energy Physics - Phenomenology · Physics 2009-12-08 Carlos G. Granados , Misak M. Sargsian

When the new data on polarised lepton nucleon scattering are compared at the same value of $Q^2$ and with a common set of assumptions, a consistent picture of the spin content of the nucleon begins to emerge. Higher order effects in…

High Energy Physics - Phenomenology · Physics 2007-05-23 F. E. Close

A whole class of non-perturbative QCD studies, e.g. the instanton models, chiral quark models, etc. indicates that the effective degrees of freedom for the physics in the low Q^(2) < 1 GeV^(2) region could be the constituent quarks (CQs)…

High Energy Physics - Phenomenology · Physics 2007-05-23 T. P. Cheng , Ling-Fong Li

Understanding hadron structure within the framework of QCD is an extremely challenging problem. In order to solve it, it is vital that our thinking should be guided by the best available insight. Our purpose here is to explain the model…

High Energy Physics - Phenomenology · Physics 2010-02-17 D. B. Leinweber , A. W. Thomas , R. D. Young

The proton spin puzzle has challenged our understanding of QCD for the last 20 years. We survey new developments in theory and experiment. The proton spin puzzle seems to be telling us about the interplay of valence quarks with chiral…

High Energy Physics - Phenomenology · Physics 2017-08-23 Steven D. Bass

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

We present results of a perturbative QCD analysis of deep inelastic measurements of both the deuteron and proton structure functions. We evaluate the theoretical uncertainty associated to nuclear effects in the deuteron, and we extract…

High Energy Physics - Phenomenology · Physics 2014-11-17 S. I. Alekhin , S. A. Kulagin , S. Liuti

The flavor and spin structure for the quark distributions of the $\Lambda$-baryon is studied in a perturbative QCD (pQCD) analysis and in the SU(6) quark-diquark model, and then applied to calculate the $\Lambda$-polarization of…

High Energy Physics - Phenomenology · Physics 2009-10-31 Bo-Qiang Ma , Ivan Schmidt , Jian-Jun Yang

The alternative to the standard formulation of the quark-parton model is proposed. Our relativistically covariant approach is based on the solution of the master equations relating the structure and distribution functions, which…

High Energy Physics - Phenomenology · Physics 2007-05-23 Petr Zavada

We briefly review the structure of nucleon in the context of QCD, Constituent Quark Model and Chiral Quark Model.

High Energy Physics - Phenomenology · Physics 2007-05-23 Manmohan Gupta , Harleen Dahiya

General arguments suggest that the non-perturbative background field in QCD may have a non-trivial spin structure. We discuss how this effect may be manifest in semi-inclusive measurements of fast pions in polarised deep inelastic…

High Energy Physics - Phenomenology · Physics 2009-10-28 S. D. Bass

I begin with a general discussion about importance of constructing a picture of the nucleon in terms of QCD degrees of freedom, emphasizing the role of spin structure functions. I then give a short overview on the theoretical and…

High Energy Physics - Phenomenology · Physics 2007-05-23 Xiangdong Ji

I review recent theoretical results on polarized deep inelastic lepton nucleon scattering. Some specific issues, like $Q^2$ evolution of structure functions, the small $x$ behaviour, and the determination of polarized parton densities, are…

High Energy Physics - Phenomenology · Physics 2007-05-23 Giovanni Ridolfi

The quark spin densities related to generalized parton distributions in impact-parameter space and to transverse-momentum dependent parton distributions are reviewed within a light-cone quark model, with focus on the role of the different…

High Energy Physics - Phenomenology · Physics 2015-05-14 B. Pasquini , S. Boffi , P. Schweitzer

Recent progress in the field of spin physics of high energy particle interactions is reviewed with particular emphasis on the spin structure functions as measured in polarized deep inelastic lepton-nucleon scattering (DIS). New measurements…

High Energy Physics - Experiment · Physics 2011-07-19 Uta Stosslein