Small- and large-x nucleon spin structure from a global QCD analysis of polarized Parton Distribution Functions

Abstract

I investigate the behavior of spin-dependent parton distribution functions in the regions of small and large momentum fractions $x$. I present a systematic comparison between predictions for relevant observables obtained with various models of nucleon spin structure and a recent global analysis of spin-dependent distributions, NNPDFpol1.1. Together with its unpolarized counterpart, NNPDF2.3, they form a mutually consistent set of parton distributions. Because they include most of the available experimental information, and are determined with a minimally biased methodology, these are especially suited for such a study. I show how NNPDFpol1.1 can discriminate between different theoretical models, even though NNPDF uncertainties remain large near the endpoints $x\to 0$ and $x\to 1$, due to the lack of experimental information. I discuss how our knowledge of nucleon spin structure may be improved at small-$x$ by future measurements at an Electron-Ion Collider, and at large-$x$ by recent measurements at Jefferson Lab, also in view of its $12$ GeV upgrade.

arXiv comment10 pages, 6 figures, version to be published in Phys.Lett.B

References in corpus (46)

• Parton distributions with LHC data
• Measurements of the Proton and Deuteron Spin Structure Functions g1 and g2
• Extraction of Spin-Dependent Parton Densities and Their Uncertainties
• Uncertainties of predictions from parton distributions. I: experimental errors
• The theory and phenomenology of polarized deep inelastic scattering
• Precise determination of the spin structure function ${\mathbf{g}}_1$ of the proton, deuteron and neutron
• A first unbiased global determination of polarized PDFs and their uncertainties
• Precision Determination of the Neutron Spin Structure Function g1n
• Physics Opportunities with the 12 GeV Upgrade at Jefferson Lab
• Evidence for polarization of gluons in the proton
• QCD Constrains on the Shape of Polarized Quark and Gluon Distributions
• Measurements of the $Q^2$-Dependence of the Proton and Neutron Spin Structure Functions g1p and g1n
• Precision Measurement of the Neutron Spin Asymmetries and Spin-dependent Structure Functions in the Valence Quark Region
• Determination of Polarized PDFs from a QCD Analysis of Inclusive and Semi-inclusive Deep Inelastic Scattering Data
• The Spin-dependent Structure Function of the Proton g_1^p and a Test of the Bjorken Sum Rule
• Higgs production in gluon fusion beyond NNLO
• Spin Structure of the Nucleon - Status and Recent Results
• Semileptonic Hyperon Decays
• QCD Analysis of the Polarized World Data
• QCD Analysis of Polarized Deep Inelastic Scattering Data
• Parton Distribution Benchmarking with LHC Data
• Flavor Singlet Contribution to the Structure Function $g_1$ at Small-x
• Measurement of the $x$- and $Q^2$-Dependence of the Asymmetry $A_1$ on the Nucleon
• A statistical approach for polarized parton distributions
• Valence Quark Spin Distribution Functions
• Determination of gluon polarization from deep inelastic scattering and collider data
• Nucleon quark distributions in a covariant quark-diquark model
• Nucleon spin structure at very high-x
• The Singlet Contribution to the Structure Function $g_1(x,Q^2)$ at Small $x$
• NLO QCD Analysis of Polarized Deep Inelastic Scattering
• Scale Dependence and Small-x Behaviour of Polarized Parton Distributions
• Impact of hadronic and nuclear corrections on global analysis of spin-dependent parton distributions
• Effect of Orbital Angular Momentum on Valence-Quark Helicity Distributions
• The Spin Dependence of Diffractive Processes and Implications for the Small $x$ Behaviour of $g_1$ and the Spin Content of the Nucleon
• Symmetry breaking and quark-hadron duality in structure functions
• An exact sum rule for transversely polarized DIS
• Precision measurements of $g_1$ of the proton and the deuteron with 6 GeV electrons
• Parton Distributions for the Octet and Decuplet Baryons
• Helicity Parton Distributions at a Future Electron-Ion Collider: A Quantitative Appraisal
• The small $x$ behaviour of $g_1$
• QCD analysis of polarized DIS and the SIDIS asymmetry world data and light sea-quark decomposition
• Running coupling effects for the singlet structure function g_1 at small x
• Polarized Parton Distributions at an Electron-Ion Collider
• Analytic Approaches to the Evolution of Polarised Parton Distributions at Small $x$
• Instantons and Polarized Structure Functions
• Spin constraints on Regge predictions and perturbative evolution in high energy collisions

Cited by in corpus (22)

• Parton distributions and lattice QCD calculations: a community white paper
• Parton distributions and lattice QCD calculations: toward 3D structure
• The Spin Structure Function $g_1^{\mathrm{p}}$ of the Proton and a Test of the Bjorken Sum Rule
• A Hybrid Renormalization Scheme for Quasi Light-Front Correlations in Large-Momentum Effective Theory
• The asymptotic behaviour of parton distributions at small and large $x$
• Novel approaches in Hadron Spectroscopy
• Next-to-next-to-leading order QCD analysis of spin-dependent parton distribution functions and their uncertainties: Jacobi polynomials approach
• Wigner distributions and orbital angular momentum of a proton
• Unified Description of Polarized and Unpolarized Quark Distributions in the Proton
• Nucleon resonance contributions to unpolarised inclusive electron scattering
• Complementarity of experimental and lattice QCD data on pion parton distributions
• Hadron mass corrections in semi-inclusive deep-inelastic scattering
• Resonant contributions to inclusive nucleon structure functions from exclusive meson electroproduction data
• On the small-$x$ behavior of the orbital angular momentum distributions in QCD
• Determination of neutron fracture functions from a global QCD analysis of leading neutron production at HERA
• Impact of recent COMPASS data on polarized parton distributions and structure functions
• Parton distribution functions with QED corrections in the valon model
• Unbiased polarized PDFs upgraded with new inclusive DIS data
• Global QCD Analysis of Pion Parton Distributions with Threshold Resummation
• Effect of symmetry breaking of polarized light sea quarks on the nucleon and nuclear structure functions, and sum rules
• Achievements and open issues in the determination of polarized parton distribution functions
• Toward Precision Helicity PDFs from Global DIS and SIDIS Fits with Projected EIC Measurements