[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] TRIUMF experiment 497 has measured the parity-violating longitudinal analyzing power A_z in p(vector sign)p elastic scattering at 221.3 MeV incident proton energy. This comprehensive paper includes details of the corrections, some of magnitude comparable to A_z itself, required to arrive at the final result. The largest correction was for the effects of first moments of transverse polarization. The addition of the result, A_z=[0.84±0.29 (stat.)±0.17 (syst.)]x10^-7, to the p(vector sign)p parity-violation experimental data base greatly improves the experimental constraints on the weak meson-nucleon coupling constants h_ρ^pp and h_ω^pp, and also has implications for the interpretation of electron parity-violation experiments

[en] Parity violation in proton-proton elastic scattering provides a unique window on the hadronic weak interaction. At low and intermediate energies, the coupling constants of an effective meson exchange model provide an appropriate parametrization. Measurements at different beam energies permit the lowest partial wave amplitudes to be determined in a model independent framework. The TRIUMF cyclotron provides a unique opportunity to measure the ³P₂-¹D₂ contribution to proton-proton parity violation at 221 MeV beam energy. This partial wave in turn isolates the weak ρ meson exchange contribution, which is only known to within a factor of 2 from theoretical estimates. An experiment underway for many years at TRIUMF completed data taking in 1999, and the analysis is now nearing completion. Preliminary results, based on half of the acquired data sample, are consistent with the meson exchange model prediction at this beam energy

[en] An experiment (E497) is underway at TRIUMF to measure the angle-integrated, parity violating longitudinal analyzing power, A_z, in proton-proton elastic scattering, to a precision of ±0.2x10^-7. The experiment uses a 221 MeV longitudinally polarized proton beam incident on a 40 cm liquid hydrogen target. The beam energy is carefully chosen so that the contribution to A_z from the J=0 parity mixed partial wave (¹S₀-³P₀) integrates to zero over the acceptance of the apparatus, leaving the experiment sensitive mainly (>95%) to A_z arising from the ³P₂-¹D₂, J=2 wave. To minimize sources of systematic error, the TRIUMF ion source and cyclotron parameters have been refined to the extent that helicity correlated beam changes are at an extremely low level, and specialized instrumentation on the E497 beamline is able to measure residual helicity correlated modulations to a precision consistent with the goals of the experiment. A data taking run in February-March, 1997 logged approximately 12% of the desired data and produced a preliminary result, A_z=(1.1±0.4±0.4)x10^-7, where the error is statistical only. copyright 1997 American Institute of Physics

[en] Recoil proton polarization observables were measured for both the p(rvec e,e^' rvec p) and d(rvec e,e^' rvec 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-dependent observables D_scr(ll) and D_scr(l)t , 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). copyright 1998 The American Physical Society

[en] The first measurements of the induced proton polarization P_n for the ¹²C( e,e^'rvec p) reaction are reported. The experiment was performed at quasifree kinematics for energy and momentum transfer (ω,q)∼ (294 MeV, 756 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 1p_3/2 shell. The data for the continuum suggest that both the 1s_1/2 shell and underlying scr(l)>1 configurations contribute. copyright 1998 The American Physical Society

[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. copyright 1998 The American Physical Society