Spin correlations in quasi-elastic electron scattering from a (3)He internal target.

摘要

The measurement of spin observables in the 3He&ar; e&ar;,e' ,d and 3He&ar; e&ar;,e' ,p reactions have been carried out at the Internal Target Facility of the Dutch National Institute for Nuclear and High Energy Physics (NIKHEF) in Amsterdam, The Netherlands, with a 720-MeV stored electron beam having a longitudinal polarization of 65% and an average current of 80 mA. This was the first measurement of the spin correlation parameters for the reaction 3He&ar; e&ar;,e' ,d . The average target polarization was 45% with a thickness of 5 x 1014 atoms/cm2. The scattered electrons were detected in a large-acceptance, nonfocusing magnetic spectrometer located at a central angle of 40°. The knockout hadrons were detected in a non-magnetic detector located at a central angle of --56°. The central positions of the detectors correspond to quasi-elastic kinematics. The asymmetries A'x and A'x provide information on small components of the 3He ground-state wave function and on the isoscalar/isovector structure of the nuclear electromagnetic current. The results are compared with model calculations.