[en] In elastic electron-deuteron scattering, the tensor polarization moments t₂₀, t₂₁ and t₂₂, together with the unpolarized cross-sections, have been measured up to a momentum transfer of 1.8 (GeV/c)², or 6.8 fm^-1. The experiment was performed at Jefferson Laboratory using the recoil deuteron polarimeter POLDER. Preliminary results are presented and discussed, especially in view of their significance concerning the applicability of perturbative QCD to this exclusive process

[en] We report the results of a new Rosenbluth measurement of the proton form factors at Q² values of 2.64, 3.20 and 4.10 GeV². Cross sections were determined by detecting the recoiling proton in contrast to previous measurements in which the scattered electron was detected. At each Q², relative cross sections were determined to better than 1%. The measurement focused on the extraction of G_E/G_M which was determined to 4-8% and found to approximate form factor scaling, i.e. μ_pG_E ∼ G_M. These results are consistent with and much more precise than previous Rosenbluth extractions. However, they are inconsistent with recent polarization transfer measurements of comparable precision, implying a systematic difference between the two techniques

[en] The A(Q²) structure function in elastic electron-deuteron scattering was measured at six momentum transfers Q² between 0.66 and 1.80 (GeV/c)² in Hall C at Jefferson Laboratory. The scattered electrons and recoil deuterons were detected in coincidence, at a fixed deuteron angle of 60.5^o. These new precise measurements resolve discrepancies between older sets of data. They put significant constraints on existing models of the deuteron electromagnetic structure, and on the strength of isoscalar meson exchange currents

[en] The A(e,eiK+)YX reaction on H, D, ³He, and ⁴He was investigated in Hall C at CEBAF. Data were obtained for Q² ∼ 0.35 and 0.5 GeV² at 3.245 GeV. The missing mass spectra for both H and D are fitted with Monte-Carlo simulations incorporating peaks corresponding to Lambda production on the proton and Sigma production on both the proton and neutron. For D, the cross section ratio Sigma⁰/Sigma^- ∼ 2, and excess yield close to the thresholds for Lambda and Sigma production can be attributed to final-state interactions; models are compared to the data. The analysis of the data for the He targets is in a more preliminary state with broader quasi-free peaks resulting from the higher Fermi momenta. Evidence for bound Lambda-hypernuclear states is seen and other structure may be present

[en] Kaon electroproduction on hydrogen, deuterium and helium targets has been measured at a beam energy of 3.245 GeV and four-momentum transfer, Q², ranging from 0.34 to 0.5 GeV². Associated hyperon production off a nucleon in the deuteron exhibits a quasifree production mechanism. Excess yield close to the respective thresholds for Λ and Σ production is observed. This can be accounted for by final-state interaction between the electroproduced hyperon and the spectator nucleon. The effects predicted from three different hyperon-nucleon potentials are compared to the data. The measurement on the helium targets is the first ever performed. Very preliminary results are presented

[en] The A(e,eK+)X reaction has been investigated at Jefferson Laboratory. Data were taken for Q² approx. 0.35 GeV² at a beam energy of 3.245 GeV for 1H,3He and 4He targets. Evidence for Lambda-hypernuclear bound states is seen for 3,4He targets. This is the first time that the electroproduction of these hypernuclei has been observed