A Next-to-Leading Determination of the Singlet Axial Charge and the Polarized Gluon Content of the Nucleon

Abstract

We perform a full next-to-leading analysis of the the available experimental data on the polarized structure function g_1 of the nucleon, and give a precise determination of its singlet axial charge together with a thorough assessment of the theoretical uncertainties. We find that the data are now sufficient to separately determine first moments of the polarized quark and gluon distributions, and show in particular that the gluon contribution is large and positive.

arXiv comment19 pages, TeX with harvmac and epsf, 4 figures in compressed postscript. All the data analysis redone incorporating a recent correction to the NLO anomalous dimensions of Mertig and van Neerven. Eq.(15) modified accordingly. All numerical results and conclusions essentially unchanged

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• Measurement of the Spin-Dependent Structure Function $g_1(x)$ of the Proton
• QCD Constrains on the Shape of Polarized Quark and Gluon Distributions
• Double Asymptotic Scaling at HERA
• The next-to-leading QCD approximation to the Ellis-Jaffe sum rule
• Summation of Leading Logarithms at Small x
• Scale Dependence and Small-x Behaviour of Polarized Parton Distributions
• Spin Contents of Nucleons with SU(3) Breaking
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Cited by in corpus (85)

• The Spin Structure of the Nucleon
• Models for the Polarized Parton Distributions of the Nucleon
• Measurements of the Proton and Deuteron Spin Structure Functions g1 and g2
• Precision Determination of the Neutron Spin Structure Function g1n
• Measurement of the Neutron Spin Structure Function $g_1^n$ with a Polarized ^3He Target
• Spin Structure of the Proton from Polarized Inclusive Deep-Inelastic Muon-Proton Scattering
• QCD Analysis of Polarized Deep Inelastic Data and Parton Distributions
• Spin Physics and Polarized Structure Functions
• Determination of the Bjorken Sum and Strong Coupling from Polarized Structure Functions
• The Spin Structure of the Proton
• The Spin Structure of the Nucleon
• Polarized Parton Distribution Functions in the Nucleon
• Spin Structure of the Nucleon - Status and Recent Results
• Measurement of the Spin Asymmetry in the Photoproduction of Pairs of High-pT Hadrons at HERMES
• Gluon polarization in the nucleon from quasi-real photoproduction of high-pT hadron pairs
• Next-to-Leading Order QCD Analysis of Polarized Deep Inelastic Scattering Data
• The Spin Structure of the Nucleon
• Strangeness in the nucleon: neutrino-nucleon and polarized electron-nucleon scattering
• Valence Quark Spin Distribution Functions
• Target mass effects in polarized deep-inelastic scattering
• Mellin Representation for the Heavy Flavor Contributions to Deep Inelastic Structure Functions
• NLO QCD Analysis of Polarized Deep Inelastic Scattering
• Leading and higher twists in the proton polarized structure function at large Bjorken x
• On positivity of parton distributions
• Spin-Dependent Twist-Four Matrix Elements from g_1 Data in the Resonance Region
• Polarized Parton Densities in the Nucleon
• Evolution Equations for Higher Moments of Angular Momentum Distributions
• Spin - Dependent Parton Distributions of the Longitudinally Polarized Photon Beyond the Leading Order
• Next-to-leading order jet cross sections in polarized hadronic collisions
• Next-to-Leading Order Analysis of Inclusive and Semi-inclusive Polarized Data
• Scheme Dependence in Polarized Deep Inelastic Scattering
• Generalized form factors, generalized parton distributions and the spin contents of the nucleon
• A New Study of the Polarized Parton Densities in the Nucleon
• Topological Charge Screening and the `Proton Spin' Beyond the Chiral Limit
• Polarized parton distributions from charged-current deep-inelastic scattering and future neutrino factories
• Polarized Parton Distributiions and Light-Front Dynamics
• The Gauge-Invariant Angular Momentum Sum-Rule for the Proton
• QCD Corrections to Double and Single Spin Asymmetries in Vector Boson Production at Polarized Hadron Colliders
• QCD corrections to the longitudinally polarized Drell-Yan process
• Polarized structure functions in a constituent quark scenario
• Spin Structure Function of the Virtual Photon Beyond the Leading Order in QCD
• Polarized Parton Distributions in the Photon and Factorization Scheme Dependence
• Spin and Orbital Angular Momentum Distribution Functions of the Nucleon
• Probing Nucleon Spin Structure
• Scale- and scheme-independent extension of Pade approximants; Bjorken polarized sum rule as an example
• Helicity-dependent generalized parton distributions and composite constituent quarks
• Next-to-leading order QCD corrections to inclusive-hadron photoproduction in polarized lepton-proton collisions
• The Role of Polarized Valons in the Flavor Symmetry Breaking of Nucleon Sea
• Non-local generalization of the axial anomaly and $x$-dependence of the anomalous gluon contribution
• Gluon Spin in a Quark Model
• Testing Target Independence of the `Proton Spin' Effect in Semi-Inclusive Deep Inelastic Scattering
• Neutron spin-dependent structure function, Bjorken sum rule, and first evidence for singlet contribution at low $x$
• Isolated Photons at Hadron Colliders at O(αalpha_s^2) (II): Spin Dependent Case
• Next to Leading Order QCD Corrections to Polarized $\Lambda$ Production in DIS
• Measuring Polarized Gluon and Quark Distributions with Meson Photoproduction
• Remarks on Next-to-Leading Order Analysis of Polarized Deep Inelastic Scattering Data
• Inclusive Prompt Photon Production in Polarized pp Collisions at HERA-N
• A QCD Analysis of Polarised Parton Densities
• The Spin Structure of the Proton and Polarized Collider Physics
• Instantons and Polarized Structure Functions
• Spin of ground state baryons
• Summary of Physics Prospects for Polarized Nucleon-Nucleon Scattering at HERA-N
• Spin Physics
• The `Proton Spin' Effect - Theoretical Status '97
• Moments of generalized parton distribution functions and the nucleon spin contents
• Spin structure in non-forward partons
• Gluon Polarization from QCD Sum Rules
• Gluon polarization in the proton
• Polarized parton distributions in perturbative QCD
• Conatraints on $\Delta G$ from Prompt Photon plus Jet Production at HERA-$\vec{N}$
• Proton spin structure and the axial U(1) problem
• Understanding nucleon structure using lattice simulations
• Deciphering Twist-3 Chiral-Even GPDs in the Light-Front Quark-Diquark Model
• Target Fragmentation in Semi-Inclusive DIS: Fracture Functions, Cut Vertices and the OPE
• Different behaviour of the spin structure functions $g_1(x)$ and $h_1(x)$ at $x\to 0$
• Parton Distributions in the Virtual Photon Target and Factorization Scheme Dependence
• The U(1)_A Anomaly and QCD Phenomenology
• A Test of Target Independence of the `Proton Spin' Effect in Semi-Inclusive Deep Inelastic Scattering
• A Short Review and Some New Results on Polarization
• An Alternative Method to Obtain the Quark Polarization of the Nucleon
• Parton distributions in a constituent quark scenario
• Results on the nucleon spin structure
• Scheme Independence of $g_1^p(x,Q^2)$
• Evolution of Gluon Spin in the Nucleon
• Fracture functions in the very forward limit