[en] The first measurements of the induced proton polarization Pn for the 12C(e,e',p) reaction are reported. The experiment was performed at quasifree kinematics for energy and momentum transfer (w,q) = (294 MeV, 765 MeV/c) and sampled a missing momentum range of 0-250 MeV/c. The induced polarization arises from final-state interactions and for these kinematics is dominated by the real part of the spin-orbit optical potential. The distorted-wave impulse approximation provides good agreement with data for the 1 p3/2 shell. The data for the continuum suggest that both the 1s1/2 shell and underlying l > 1 configurations contribute

[en] Recoil proton polarization observables were measured for both the p(e,e'p) and d(e,e'p)n reactions at two values of Q2 using a newly commissioned proton focal plane polarimeter at the MIT-Bates Linear Accelerator Center. The hydrogen and deuterium spin-depended observables Dll and Dl, the induced polarization Pn, and the form factor ratio Gpe/Gpm 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)

[en] We present a measurement of the induced proton polarization P_n in π⁰ electroproduction on the proton around the Δ resonance. The measurement was made at a central invariant mass and a squared four-momentum transfer of W = 1231 MeV and Q² = 0.126 GeV²/c², respectively. We measured a large induced polarization, P_n = -0.397 ± 0.055 ± 0.009. The data suggest that the scalar background is larger than expected from a recent effective Hamiltonian model

[en] 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. 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

[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 Q² the deuteron charge form factors G_C and G_Q. They are in good agreement with relativistic calculations and disagree with pQCD predictions

[en] The ratio of the proton's elastic electromagnetic form factors, G(E_p)/G(M_p) was obtained by measuring P_i and P_l, the transverse and the longitudinal recoil proton polarization, respectively. For elastic ep to ep, G(E_p)/G(M_p) is proportional to P_t/P_l. Simultaneous measurement of P_t and P_l in a polarimeter provides good control of the systematic uncertainty. The results for the ratio G(E_p)/G(M_p) show a systematic decrease as Q² increases from 0.5 to 3.5 GeV², indicating for the first time a definite difference in the spatial distribution of charge and magnetization currents in the proton

[en] The ratio of the proton's elastic electromagnetic form factors, G_Ep/G_Mp was obtained by measuring P_i and P_l, the transverse and the longitudinal recoil proton polarization, respectively. For elastic ep to ep, G_Ep/G_Mp is proportional to P_t/P_l. Simultaneous measurement of P_t and P_l in a polarimeter provides good control of the systematic uncertainty. The results for the ratio G_Ep/G_Mp show a systematic decrease as Q² increases from 0.5 to 3.5 GeV², indicating for the first time a definite difference in the spatial distribution of charge and magnetization currents in the proton

[en] We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from protons. Significant contributions to this asymmetry could arise from the contributions of strange form factors in the nucleon. The measured asymmetry is A = -15.05 ± 0.98(stat) ± 0.56(syst) ppm at the kinematic point <θ_lab> = 12.3^o and < Q²> = 0.477 (GeV/c)². Based on these data as well as data on electromagnetic form factors, we extract the linear combination of strange form factors G_E^s + 0.392G_M^s = 0.014 ± 0.020 ± 0.010 where the first error arises from this experiment and the second arises from the electromagnetic form factor data. This paper provides a full description of the special experimental techniques employed for precisely measuring the small asymmetry, including the first use of a strained GaAs crystal and a laser-Compton polarimeter in a fixed target parity-violation experiment

[en] We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from the proton. The result is A = -15.05 +- 0.98(stat) ± 0.56(syst) ppm at the kinematic point theta_lab = 12.3 degrees and Q² = 0.477 (GeV/c)². The measurement implies that the value for the strange form factor (G_E^s + 0.392 G_M^s)/(G_M^p μ_p) = 0.069 +- 0.056 +- 0.039, where the first error is experimental and the second arises from the uncertainties in electromagnetic form factors. This measurement is the first fixed-target parity violation experiment that used either a ''strained'' GaAs photocathode to produce highly polarized electrons or a Compton polarimeter to continuously monitor the electron beam polarization

[en] The ratio of the proton's elastic electromagnetic form factors, G_Ep/G_Mp was obtained by measuring P_t and P(ell), the transverse and the longitudinal recoil proton polarization, respectively. For elastic ep → ep, G_Ep/G_Mp is proportional to P_t/P(ell). Simultaneous measurement of P_t and P(ell) in a polarimeter provides good control of the systematic uncertainty. The results for the ratio G_Ep/G_Mp show a systematic decrease as Q² increases from 0.5 to 3.5 GeV², indicating for the first time a definite difference in the spatial distribution of charge and magnetization currents in the proton