Precise Determination of the Deuteron Spin Structure at Low to Moderate $Q^2$ with CLAS and Extraction of the Neutron Contribution

Abstract

We present the final results for the deuteron spin structure functions obtained from the full data set collected with Jefferson Lab's CLAS in 2000-2001. Polarized electrons with energies of 1.6, 2.5, 4.2 and 5.8 GeV were scattered from deuteron (${}^{15}$ND${}_3$) targets, dynamically polarized along the beam direction, and detected with CLAS. From the measured double spin asymmetry, the virtual photon absorption asymmetry $A_1^d$ and the polarized structure function $g_1^d$ were extracted over a wide kinematic range (0.05 GeV${}^2<Q^2<$ 5 GeV${}^2$ and 0.9 GeV $<W<$ 3 GeV). We use an unfolding procedure and a parametrization of the corresponding proton results to extract from these data the polarized structure functions $A_1^n$ and $g_1^n$ of the (bound) neutron, which are so far unknown in the resonance region, $W<2$ GeV. We compare our final results, including several moments of the deuteron and neutron spin structure functions, with various theoretical models and expectations as well as parametrizations of the world data. The unprecedented precision and dense kinematic coverage of these data can aid in future extractions of polarized parton distributions, tests of perturbative QCD predictions for the quark polarization at large $x$, a better understanding of quark-hadron duality, and more precise values for higher-twist matrix elements in the framework of the Operator Product Expansion.

To be published in Phys. Rev. C

References in corpus (15)

• The Deuteron Spin-dependent Structure Function g1d and its First Moment
• Spin Structure of the Nucleon - Status and Recent Results
• Empirical Fit to Inelastic Electron-Deuteron and Electron-Neutron Resonance Region Transverse Cross Sections
• Measurement of the structure function of the nearly free neutron using spectator tagging in inelastic ${}^2$H(e, e'p)X scattering with CLAS
• High precision determination of the $Q^2$-evolution of the Bjorken Sum
• 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
• New analysis concerning the strange quark polarization puzzle
• 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
• Proton Spin Structure in the Resonance Region
• Nucleon spin structure at low momentum transfers
• Quark-Hadron Duality in Neutron (3He) Spin Structure
• Higher twists in polarized DIS and the size of the constituent quark
• New results in the quantum statistical approach to parton distributions

Cited by in corpus (28)

• Iterative Monte Carlo analysis of spin-dependent parton distributions
• The Spin Structure of the Nucleon
• Determination of the Proton Spin Structure Functions for 0.05 < Q^2 < 5 GeV^2 using CLAS
• First analysis of world polarized DIS data with small-$x$ helicity evolution
• Measurement of the Q^2 Dependence of the Deuteron Spin Structure Function g_1 and its Moments at Low Q^2 with CLAS
• Analytical approaches to the determination of spin-dependent parton distribution functions at NNLO approximation
• Longitudinal double-spin asymmetry for inclusive jet and dijet production in polarized proton collisions at $\sqrt{s}=200$ GeV
• Forward doubly-virtual Compton scattering off the nucleon in chiral perturbation theory: II. Spin polarizabilities and moments of polarized structure functions
• Measurement of the proton spin structure at long distances
• Measurement of the 3He Spin-Structure Functions and of Neutron (3He) Spin-Dependent Sum Rules at 0.035<Q^2<0.24 GeV^2
• Radiative corrections to semileptonic beta decays: Progress and challenges
• Measurement of the generalized spin polarizabilities of the neutron in the low $Q^2$ region
• Polarised parton distribution functions and proton spin
• Future tests of parton distributions
• Updating spin-dependent Regge intercepts
• Nucleon polarizabilities in covariant baryon chiral perturbation theory with explicit $\Delta$ degrees of freedom
• Target and Beam-Target Spin Asymmetries in Exclusive Pion Electroproduction for $Q^2>1$ GeV${}^2$. I. $ep\to e{\pi }^{+}n$
• Beam-target double spin asymmetry in quasi-elastic electron scattering off the deuteron with CLAS
• Sensitivity of strange quark polarization to flavor SU(3) symmetry breaking
• Strange quark helicity in the proton from chiral effective theory
• Target and Beam-Target Spin Asymmetries in Exclusive ${\pi }^{+}$ and ${\pi }^{-}$ Electroproduction with 1.6 to 5.7 GeV Electrons
• Measurement of the nucleon spin structure functions for 0.01<$Q^2$<1 GeV${}^2$ using CLAS
• Detailed Study of Quark-Hadron Duality in Spin Structure Functions of the Proton and Neutron
• Can sea quark asymmetry shed light on the orbital angular momentum of the proton?
• Helicity-dependent distribution of strange quarks in the proton from nonlocal chiral effective theory
• Experimental studies at low $Q^2$ of the spin structure of the nucleon at Jefferson Lab
• The Gerasimov-Drell-Hearn sum-rule with nuclear targets
• Toward Precision Helicity PDFs from Global DIS and SIDIS Fits with Projected EIC Measurements