J. Van de Wiele

Measurement of Strange Quark Contributions to the Vector Form Factors of the Proton at Q2 = 0.22 (GeV/c)2

A new measurement of the parity violating asymmetry in elastic electron scattering on hydrogen at backward angles and at a four momentum transfer of Q;{2} = 0.22 (Ge V / c);{2} is reported here. The measured asymmetry is A_{LR} = (-17.23 +/- 0.82_{stat} +/- 0.89_{syst}) x 10;{-6}. The standard model prediction assuming no strangeness is A_{0} = (-15.87 +/- 1.22) x 10;{-6}. In combination with previous results from measurements at forward angles, it is possible to disentangle for the first time the strange form factors at this momentum transfer, G_{E};{s} = 0.050 +/- 0.038 +/- 0.019 and G_{M};{s} = -0.14 +/- 0.11 +/- 0.11.

QED radiative corrections to virtual Compton scattering

The QED radiative corrections to virtual Compton scattering (reaction

Measurement of the Inclusive

e p \to e p \gamma

p

) are calculated to first order in

C Analyzing Power and Cross-section in the 1-{GeV} Region and Calibration of the New Polarimeter Pomme

\alpha_{em} \equiv e^2 / 4 \pi

Excitation of inner hole states in heavy nuclei with the (τ, α) reaction at 205 MeV

. A detailed study is presented for the one-loop virtual corrections and for the first order soft-photon emission contributions. Furthermore, a full numerical calculation is given for the radiative tail, corresponding with photon emission processes, where the photon energy is not very small compared with the lepton momenta. We compare our results with existing works on elastic electron-proton scattering, and show for the

First determination of generalized polarizabilities of the proton by a virtual compton scattering experiment.

e p \to e p \gamma

New evidence for deep-lying hole strength in 115Sn and 207Pb via the (3He, α) reaction at 283 MeV

reaction how the observables are modified due to these first order QED radiative corrections. We show results for both unpolarized and polarized observables of the virtual Compton scattering in the low energy region (where one is sensitive to the generalized polarizabilities of the nucleon), as well as for the deeply virtual Compton scattering.

Étude du mécanisme de la réaction (3He, α)à217 (205) MeV et de l'excitation d'état de trous dans les couches profondes

Abstract We describe the polarimeter POMME, and give the results of its calibration in the region 200–1200 MeV, using the Saturne polarized proton beam. The high energy part of this domain (800–1200 MeV) was previously unexplored. Parametrizations of the inclusive p-C analyzing power and polarimeter efficiency as a function of scattering angle and incident energy are given, completing the data already available at lower energies. The optimization of proton polarimeters in this energy domain is also discussed.

Feasibility studies of the time-like proton electromagnetic form factor measurements with

Abstract Energy spectra have been measured for the (τ, α) reaction at 205 MeV on 90 Zr, 118,124 Sn and 208 Pb. Results on the valence neutron shells and on the inner 1f 7/2 shell in 90 Zr, 1g 9/2 subshell in 118,124 Sn ( T and T > components) and 1h 11/2 subshell in 208 Pb are presented.