[en] Three experiments at JLab have measured the double polarization asymmetries in the nucleon resonance region, using polarized electron beams incident on polarized proton and deuteron targets. The analysis for the first experiment, eg1a in Hall B, is nearly finished and preliminary values of the spin structure function g1(x, Q2) and the first moment (x) have been extracted. The other two experiments, one in Hall B and one in Hall C, are still analyzing data. Some results are presented

[en] Double-polarization asymmetries for inclusive ep scattering were measured at Jefferson Lab using 2.6 and 4.3 GeV longitudinally polarized electrons incident on a longitudinally polarized NH₃ target in the CLAS detector. The polarized structure function g₁(x,Q²) was extracted throughout the nucleon resonance region and into the deep inelastic regime, for Q² = 0.15-1.64 GeV². The contributions to the first moment Γ₁(Q²) = g₁(x,Q²)dx were determined up to Q²=1.2 GeV². Using a parameterization for g₁ in the unmeasured low x regions, the complete first moment was estimated over this Q² region. A rapid change in Γ₁ is observed for Q² < 1 GeV², with a sign change near Q² = 0.3 GeV², indicating dominant contributions from the resonance region. At Q²=1.2 GeV² our data are below the pQCD evolved scaling value

[en] We present the Bjorken integral extracted from Jefferson Lab experiment EG1b for 0.05 < 2.92 GeV². The integral is fit to extract the twist-4 element f₂^p-n which is large and negative. Systematic studies of this higher twist analysis establish its legitimacy at Q² around 1 GeV². We also extracted the isovector part of the generalized forward spin polarizability γ₀. Although this quantity provides a robust test of Chiral Perturbation Theory, our data disagree with the calculations

[en] We extract the Bjorken integral Γ₁^p-n in the range 0.17 < Q² < 1.10 GeV² from inclusive scattering of polarized electrons by polarized protons, deuterons and ³He, for the region in which the integral is dominated by nucleon resonances. These data bridge the domains of the hadronic and partonic descriptions of the nucleon. In combination with earlier measurements at higher Q², we extract the non-singlet twist-4 matrix element f₂

[en] We report the first measurement using a solid polarized target of the neutron electric form factor Gⁿ_E via d-vector(e-vector, e'n)p. Gⁿ_E was determined from the beam-target asymmetry in the scattering of longitudinally polarized electrons from polarized deuterated ammonia (¹⁵ND₃). The measurement was performed in Hall C at Thomas Jefferson National Accelerator Facility in quasifree kinematics with the target polarization perpendicular to the momentum transfer. The electrons were detected in a magnetic spectrometer in coincidence with neutrons in a large solid angle segmented detector. We find Gⁿ_E = 0.04632±0.00616(stat)±0.00341(syst) at Q² = 0.495 (GeV/c)²

[en] The ratio of the proton's electric to magnetic form factor, G_E/G_M, can be extracted in elastic electron-proton scattering by measuring either cross sections, beam-target asymmetry or recoil polarization. Separate determinations of G_E/G_M by cross sections and recoil polarization observables disagree for Q² > 1 (GeV/c)². Measurement by a third technique might uncover an unknown systematic error in either of the previous measurements. The beam-target asymmetry has been measured for elastic electron-proton scattering at Q² = 1.51 (GeV/c)² for target spin orientation aligned perpendicular to the beam momentum direction. This is the largest Q² at which G_E/G_M has been determined by a beam-target asymmetry experiment. The result, μG_E/G_M = 0.884 +/- 0.027 +/- 0.029, is compared to previous world data

[en] We have measured the spin structure functions g₂^p and g₂^d and the virtual photon asymmetries A₂^p and A₂^d over the kinematic range 0.02 < x < 0.8 and 1.0 < Q² (le) 30(GeV/c)² by scattering 38.8 GeV longitudinally polarized electrons from transversely polarized NH₃ and ⁶LiD targets.The absolute value of A₂ is significantly smaller than the √R positivity limit over the measured range, while g₂ is consistent with the twist-2 Wandzura-Wilczek calculation. We obtain results for the twist-3 reduced matrix elements d₂^p, d₂^d and d₂ⁿ. The Burkhardt-Cottingham sum rule integral (g₂(x)dx) is reported for the range 0.02 (le) x (le) 0.8

[en] The structure functions g1p and g1n have been measured over the range 0.014 < x < 0.9 and 1 < Q2 < 40 GeV2 using deep-inelastic scattering of 48 GeV longitudinally polarized electrons from polarized protons and deuterons. We find that the Q2 dependence of g1p (g1n) at fixed x is very similar to that of the spin-averaged structure function F1p (F1n). From a NLO QCD fit to all available data we find Gamma₁^p Gamma₁ⁿ=0.176 ± 0.003 ± 0.007$ at Q2=5 GeV2, in agreement with the Bjorken sum rule prediction of 0.182 ± 0.005

[en] New measurements are reported on the deuteron spin structure function g₁^d. These results were obtained from deep inelastic scattering of 48.3 GeV electrons on polarized deuterons in the kinematic range 0.01 < x < 0.9 and 1 < Q² < 40 (GeV/c)². These are the first high dose electron scattering data obtained using lithium deuteride (⁶Li²H) as the target material. Extrapolations of the data were performed to obtain moments of g₁^d, including Γ₁^d, and the net quark polarization Δ Σ

[en] The structure functions g₁^p and g₁ⁿ have been measured over the range 0.014 < x < 0.9 and 1 < Q² < 40 GeV² using deep-inelastic scattering of 48 GeV longitudinally polarized electrons from polarized protons and deuterons. We find that the Q² dependence of g₁^p (g₁ⁿ) at fixed x is very similar to that of the spin-averaged structure function F₁^p (F₁ⁿ). From a NLO QCD fit to all available data we find Γ₁^p - Γ₁ⁿ = 0.176 ± 0.003 ± 0.007 at Q² = 5 GeV², in agreement with the Bjorken sum rule prediction of 0.182 ± 0.005