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Beam-recoil transferred polarizations for the exclusive $vec{e}p to eK^+ vec{Lambda},vec{Sigma}^0$ reactions have been measured using the CLAS spectrometer at Jefferson Laboratory. New measurements have been completed at beam energies of 4.261 and 5.754 GeV that span a range of momentum transfer $Q^2$ from 0.7 to 5.4 GeV$^2$, invariant energy $W$ from 1.6 to 2.6 GeV, and the full center-of-mass angular range of the $K^+$ meson. These new data add to the existing CLAS $K^+Lambda$ measurements at 2.567 GeV, and provide the first-ever data for the $K^+Sigma^0$ channel in electroproduction. Comparisons of the data with several theoretical models are used to study the sensitivity to s-channel resonance contributions and the underlying reaction mechanism. Interpretations within two semi-classical partonic models are made to probe the underlying reaction mechanism and the $sbar{s}$ quark-pair creation dynamics.
The recoil proton polarization has been measured in the p (vec e,evec p) pi^0 reaction in parallel kinematics around W = 1232 MeV, Q^2 = 0.121 (GeV/c)^2 and epsilon = 0.718 using the polarized c.w. electron beam of the Mainz Microtron. Due to the spi
Polarization transfer in the 4He(e,ep)3H reaction at a Q^2 of 0.4 (GeV/c)^2 was measured at the Mainz Microtron MAMI. The ratio of the transverse to the longitudinal polarization components of the ejected protons was compared with the same ratio for
The effects of multi-photon-exchange and other higher-order QED corrections on elastic electron-proton scattering have been a subject of high experimental and theoretical interest since the polarization transfer measurements of the proton electromagn
We present first measurements of the double ratio of the polarization transfer components $(P^{prime}_{!x} !/ P^{prime}_{!z} )_p/ (P^{prime}_{!x} !/ P^{prime}_{!z} )_s$ for knock-out protons from $s$ and $p$ shells in $^{12}{rm C}$ measured by the $^
First results from the longitudinally polarized frozen-spin target (FROST) program are reported. The double-polarization observable E, for the reaction $vec gamma vec p to pi^+n$, has been measured using a circularly polarized tagged-photon beam, wit