Recoil proton polarization observables were measured for both the p( e,e ′ p ) and d( e,e ′ p )n reactions at two values of Q 2 using a newly commissioned proton Focal Plane Polarimeter at the M.I.T.-Bates Linear Accelerator Center. The hydrogen and deuterium spin-dependent observables D ℓℓ and D ℓt , the induced polarization P n and the form factor ratio G p E /G p M were measured under identical kinematics. The deuterium and hydrogen results are in good agreement with each other and with the plane-wave impulse approximation (PWIA).

Tensor polarization observables (t 20 , t 21 , and t 22 ) have been measured in elastic electron-deuteron scattering for six values of momentum transfer between 0.66 and 1.7 ͑GeV͞c͒ 2 . The experiment was performed at the Jefferson Laboratory in Hall C using the electron High Momentum Spectrometer, a specially designed deuteron magnetic channel and the recoil deuteron polarimeter POLDER. The new data determine to much larger Q 2 the deuteron charge form factors G C and G Q . They are in good agreement with relativistic calculations and disagree with perturbative QCD predictions.

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A rigorous extraction of the deuteron charge form factors from tensor polarization data in elastic electron-deuteron scattering, at given values of the 4-momentum transfer, is presented. Then the world data for elastic electron-deuteron scattering is used to parameterize, in three different ways, the three electromagnetic form factors of the deuteron in the 4-momentum transfer range 0-7 fm −1 . This procedure is made possible with the advent of recent polarization measurements. The parameterizations allow a phenomenological characterization of the deuteron electromagnetic structure. They can be used to remove ambiguities in the form factors extraction from future polarization data.

We present a measurement of the induced proton polarization P n in 0 electroproduction on the proton around the ⌬ resonance. The measurement was made at a central invariant mass and a squared four-momentum transfer of Wϭ1231 MeV and Q 2 ϭ0.126 GeV 2 /c 2 , respectively. We measured a large induced polarization, P n ϭϪ0.397Ϯ0.055Ϯ0.009. The data suggest that the scalar background is larger than expected from a recent effective Hamiltonian model. ͓S0556-2813͑98͒02012-3͔ PACS number͑s͒: 13.88.ϩe, 13.60.Le, 13.60.Rj, 14.20.Gk At low Q 2 , the N→⌬ transition is dominated by the magnetic dipole amplitude. In a simple SU͑6͒ model in which all the quarks occupy S states in the N and ⌬ wave functions, the N→⌬ transition is a spin flip of a single quark. If the quarks are allowed to occupy D states as well as S states in the N or ⌬ wavefunctions, then electric and Coulomb quadrupole transitions are allowed ͓1,2͔. The ratios of these quad-*Present address: