[en] We propose to measure pion electroproduction off ¹H, ², ¹²C, ⁶⁴Cu, and ¹⁹⁷Au, and extract the pion transparency through the nuclear medium between Q² = 1 and 5 (GeV/c)². The pion transparency is predicted to be a signature of the onset of nuclear filtering and/or Color Transparency. Recent experiments have reported evidence for Color Transparency effects at Q² approx 10 (GeV/c)². The occurrence of nuclear filtering could potentially explain the apparent discrepancy between (proton) nuclear transparencies found in quasielastic A(e,e'p) and A(p,2p) experiments. The occurrence of these effects is an effective signature of the approach to the factorization regime in meson electroproduction experiments, necessary for the access to Generalized Parton Distributions. Measurable effects of approx. 40% are predicted for this region of Q². The proposed experiment seeks to measure the pion transparency with 5-10% uncertainties, dominated by systematics, up to Q² = 5 (GeV/c)²

[en] Tensor polarization observables (t20, t21 and t22) have been measured in elastic electron-deuteron scattering for six values of momentum transfer between 0.66 and 1.7 (GeV/c) 2. The experiment was performed at the Jefferson Laboratory in Hall C using the electron HMS 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 GC and GQ. They are in good agreement with relativistic calculations and disagree with pQCD predictions

[en] An experimental technique for single-Lambda spectroscopy of the light and medium-heavy mass Lambda-hypernuclei developed at the Jlab by the E01-011 Collaboration has been described. The technique is based on the electroproduction of Lambda-hypernuclei by the (e,eK+) reaction and newly constructed 2nd generation high resolution large solid angle kaon spectrometer (HKS)

[en] The ¹H(e,e(prime)π⁺)n cross section was measured for a range of four-momentum transfer up to Q²=3.91 GeV² at values of the invariant mass, W, above the resonance region. The Q²-dependence of the longitudinal component is consistent with the Q²-scaling prediction for hard exclusive processes. This suggests that perturbative QCD concepts are applicable at rather low values of Q². Pion form factor results, while consistent with the Q²-scaling prediction, are inconsistent in magnitude with perturbative QCD calculations. The extraction of Generalized Parton Distributions from hard exclusive processes assumes the dominance of the longitudinal term. However, transverse contributions to the cross section are still significant at Q²=3.91 GeV²

[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 RSS collaboration has measured the spin structure functions g₁ and g₂ of the proton at Jefferson Lab using the lab's polarized electron beam, the Hall C HMS spectrometer and the UVa polarized solid target. The asymmetries A_parallel and A_perp were measured at the elastic peak and in the region of the nucleon resonances (1.085 GeV < W < 1.910 GeV) at an average four momentum transfer of Q² = 1.3 GeV². The extracted spin structure functions and their kinematic dependence make a significant contribution in the study of higher-twist effects and polarized duality tests