Spin-dependent Parton Distributions from Polarized Structure Function Data

Abstract

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 used to test the Bjorken and Ellis-Jaffe sum rules, and also to obtain information on the parton distributions in polarized nucleons. We perform a global leading-order QCD fit to the proton deep inelastic data in order to extract the spin-dependent parton distributions. By using parametric forms which are consistent with theoretical expectations at large and small $x$, we find that the quark distributions are now rather well constrained. We assume that there is no significant intrinsic polarization of the strange quark sea. The data are then consistent with a modest amount of the proton's spin carried by the gluon, although the shape of the gluon distribution is not well constrained, and several qualitatively different shapes are suggested. The spin-dependent distributions we obtain can be used as input to phenomenological studies for future polarized hadron-hadron and lepton-hadron colliders.

23 pages, DTP/94/38

References in corpus (3)

• Measurement of the Spin-Dependent Structure Function $g_1(x)$ of the Proton
• Consistent Analysis of the Spin Content of the Nucleon
• ERRATUM TO: Power corrections $1/Q^2$ to parton sum rules for deep inelastic scattering from polarized targets

Cited by in corpus (36)

• The COMPASS Experiment at CERN
• Next-to-Leading Order Radiative Parton Model Analysis of Polarized Deep Inelastic Scattering
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• Polarized Parton Distributions in the Nucleon
• Spin Physics and Polarized Structure Functions
• Determination of ${\alpha }_s$ and the Nucleon Spin Decomposition Using Recent Polarized Structure Function Data
• Flavour and Spin of the Proton and the Meson Cloud
• Measurements of the Q2-Dependence of the Proton and Deuteron Spin Structure Functions g1p and g1d
• Deeply virtual Compton scattering in next-to-leading order
• Leading-Order Determination of the Gluon Polarization from high-$p_T$ Hadron Electroproduction
• PHENOMENOLOGICAL APPROACH TO UNPOLARIZED AND POLARIZED PARTON DISTRIBUTIONS AND EXPERIMENTAL TESTS
• Radiative Parton Model Analysis of Polarized Deep Inelastic Lepton Nucleon Scattering
• SPIN-DEPENDENT NUCLEAR STRUCTURE FUNCTIONS: GENERAL APPROACH WITH APPLICATION TO THE DEUTERON
• Structure functions for the three nucleon system
• Next-To-Leading Order Analysis of Polarized and Unpolarized Structure Functions
• QCD Evolution Equations: Numerical Algorithms from the Laguerre Expansion
• x-Dependent Polarized Parton Distributions
• Probing quark compositeness at hadronic colliders : the case of polarized beams
• Double-Spin Asymmetry of J/psi Production in Polarized pp Collisions at HERA-$\vec{N}$
• Polarized and unpolarized $\mu$-pair meson-induced Drell--Yan production and the pion distribution amplitude
• A Monte Carlo for POLarized (semi-inclusive) Deep Inelastic Scattering
• Analytic Approaches to the Evolution of Polarised Parton Distributions at Small $x$
• Spin asymmetries in one-jet production at RHIC with polarized proton beams : the effects of a hadrophilic Z'
• A model for the $Q^2$ dependence of polarized structure functions
• Extraction of the pion distribution amplitude from polarized muon pair production
• Discovery limits for a new contact interaction at future hadronic colliders with polarized beams
• The Role of Strange and Charm Quarks in the Nucleon Spin Structure Function
• Polarized Parton Distribution Functions Reexamined
• Semi-inclusive Lambda_c^+ Leptoproductions and Polarized Gluon Distributions
• Scale Dependence of Polarized DIS Asymmetries
• The final state hadrons in polarised deep inelastic scattering
• The $Q^2$ dependence of the measured asymmetry $A_1$: the test of the Bjorken sum rule
• Does One Need the Anomaly to Describe the Polarized Structure Functions?
• Nucleon longitudinal spin structure at COMPASS
• Hard Processes with Spin-Dependent Parton Distributions