Determination of the Proton Spin Structure Functions for 0.05 < Q^2 < 5 GeV^2 using CLAS

Abstract

We present the results of our final analysis of the full data set of g_1^p(Q^2), the spin structure function of the proton, collected using CLAS at Jefferson Lab in 2000-2001. Polarized electrons with energies of 1.6, 2.5, 4.2 and 5.7 GeV were scattered from proton targets (15^NH_3 dynamically polarized along the beam direction) and detected with CLAS. From the measured double spin asymmetries, we extracted virtual photon asymmetries A_1^p and A_2^p and spin structure functions g_1^p and g_2^p over a wide kinematic range (0.05 GeV^2 < Q^2 < 5 GeV^2 and 1.08 GeV < W < 3 GeV), and calculated moments of g_1^p. We compare our final results with various theoretical models and expectations, as well as with parameterizations of the world data. Our data, with their precision and dense kinematic coverage, are able to constrain fits of polarized parton distributions, test pQCD predictions for quark polarizations at large x, offer a better understanding of quark-hadron duality, and provide more precise values of higher-twist matrix elements in the framework of the Operator Product Expansion.

arXiv comment38 pages, 40 figures

References in corpus (74)

• The Cosmological Parameters 2006
• Big-Bang nucleosynthesis (Particle Data Group mini-review)
• Measurement of GEp/GMp in ep -> ep to Q2 = 5.6 GeV2
• A unitary isobar model for pion photo- and electroproduction on the proton up to 1 GeV
• The Spin Structure of the Nucleon
• Measurements of the Proton and Deuteron Spin Structure Functions g1 and g2
• Precise determination of the spin structure function ${\mathbf{g}}_1$ of the proton, deuteron and neutron
• Precision Determination of the Neutron Spin Structure Function g1n
• QCD Constrains on the Shape of Polarized Quark and Gluon Distributions
• Global analysis of proton elastic form factor data with two-photon exchange corrections
• The Deuteron Spin-dependent Structure Function g1d and its First Moment
• Deep Inelastic Scattering of Polarized Electrons by Polarized ${}^3$He and the Study of the Neutron Spin Structure
• Measurements of the $Q^2$-Dependence of the Proton and Neutron Spin Structure Functions g1p and g1n
• QCD Analysis of Polarized Deep Inelastic Data and Parton Distributions
• Measurement of the Proton Spin Structure Function g1p with a Pure Hydrogen Target
• Electroexcitation of nucleon resonances
• Measurement of the Deuteron Spin Structure Function g_1^d(x) for 1 (GeV/c)^2 < Q^2 < 40 (GeV/c)^2
• Precision Measurement of the Neutron Spin Asymmetries and Spin-dependent Structure Functions in the Valence Quark Region
• Precision Measurement of the Proton and Deuteron Spin Structure Functions g2 and Asymmetries A2
• Spin Structure of the Nucleon - Status and Recent Results
• Flavor Decomposition of the Polarized Quark Distributions in the Nucleon from Inclusive and Semi-inclusive Deep-inelastic Scattering
• Empirical Fit to Precision Inclusive Electron-Proton Cross Sections in the Resonance Region
• First measurement of the Gerasimov-Drell-Hearn integral for Hydrogen from 200 to 800 MeV
• ERRATUM TO: Power corrections $1/Q^2$ to parton sum rules for deep inelastic scattering from polarized targets
• Iterative Monte Carlo analysis of spin-dependent parton distributions
• Implications of the discrepancy between proton form factor measurements
• Measurement of the Spin Asymmetry in the Photoproduction of Pairs of High-pT Hadrons at HERMES
• Measurement of the $x$- and $Q^2$-Dependence of the Asymmetry $A_1$ on the Nucleon
• Target Mass Corrections for Polarized Structure Functions and New Sum Rules
• The Spin Structure Function $g_1^{\mathrm{p}}$ of the Proton and a Test of the Bjorken Sum Rule
• Precision Measurement of the Neutron Spin Asymmetry $A_1^n$ and Spin-Flavor Decomposition in the Valence Quark Region
• Experimental determination of the evolution of the Bjorken integral at low Q^2
• Valence Quark Spin Distribution Functions
• Impact of CLAS and COMPASS data on Polarized Parton Densities and Higher Twist
• Spin structure of the nucleon at low energies
• Q^2 Evolution of the Neutron Spin Structure Moments using a He-3 Target
• Measurement of the Proton Spin Structure Function $g_1(x,Q^2)$ for $Q^2$ from 0.15 to 1.6 GeV${}^2$ with CLAS
• Measurement of the Proton and Deuteron Spin Structure Function g_1 in the Resonance Region
• Experimental study of isovector spin sum rules
• The origins of quark-hadron duality: How does the square of the sum become the sum of the squares?
• QCD Sum Rule Calculation of Twist-4 Corrections to Bjorken and Ellis-Jaffe Sum Rules
• Signatures of Chiral Dynamics in Low Energy Compton Scattering off the Nucleon
• Generalized Drell-Hearn-Gerasimov Sum Rule at Order {\cal O}(p^4) in Chiral Perturbation Theory
• High precision determination of the $Q^2$-evolution of the Bjorken Sum
• The (alpha_s)^3 approximation of Quantum Chromodynamics to the Ellis-Jaffe sum rule
• The statistical parton distributions: status and prospects
• Nucleon spin structure and pQCD frontier on the move
• Spin asymmetry A_1^d and the spin-dependent structure function g_1^d of the deuteron at low values of x and Q^2
• Effect of Orbital Angular Momentum on Valence-Quark Helicity Distributions
• Determination of the Proton Spin Structure Functions for 0.05 < Q^2 < 5 GeV^2 using CLAS
• Spin observables and spin structure functions: inequalities and dynamics
• Moments of the Spin Structure Functions g_1^p and g_1^d for 0.05 < Q^2 < 3.0 GeV^2
• Gold-plated moments of nucleon structure functions in baryon chiral perturbation theory
• Precision measurements of $g_1$ of the proton and the deuteron with 6 GeV electrons
• Measurement of the virtual-photon asymmetry A2 and the spin-structure function g2 of the proton
• Quark-Hadron Duality in Spin Structure Functions g1p and g1d
• Q^2-Dependence of the Neutron Spin Structure Function g_2^n at Low Q^2
• Proton Spin Structure in the Resonance Region
• Measurement of Inclusive Spin Structure Functions of the Deuteron
• Precise Determination of the Deuteron Spin Structure at Low to Moderate $Q^2$ with CLAS and Extraction of the Neutron Contribution
• Measurements of $d_2^n$ and $A_1^n$: Probing the neutron spin structure
• Calculations of Higher Twist Distribution Functions in the MIT Bag Model
• OPE analysis for polarized deep inelastic scattering
• Sum Rules and Moments of the Nucleon Spin Structure Functions
• The Gerasimov-Drell-Hearn Sum Rule
• QCD radiative and power corrections and Generalized GDH sum rules
• Spin-dependent twist-4 matrix elements from the instanton vacuum: Flavor-singlet and nonsinglet
• The Spin and Flavour Dependence of High-Energy Photoabsorption
• Quark-Hadron Duality in Neutron (3He) Spin Structure
• New experimental constraints on polarizability corrections to hydrogen hyperfine structure
• Generalized sum rules of the nucleon in the constituent quark model
• Study of Instanton Contributions to Moments of Nucleon Spin-Dependent Structure Functions
• Ratios of 15N/12C and 4He/12C inclusive electroproduction cross sections in the nucleon resonance region
• The Bethe-Heitler Process in Polarized Photon-Nucleon Interactions

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