Precision studies of the 3,4He( e,e′p) reactions at MAMI

Abstract

Precision studies of the reactions 3,4 He(e,e′p) in quasi-elastic kinematics are presented. Absolute cross-sections were measured at three virtual photon polarizations for the two-body-breakup channels as well as for the missing energy continuum. For the measured missing momentum range up to 100–150 MeV/c, no strength is observed for missing energies higher than 20 MeV and 45 MeV for 3 He and 4 He , respectively. Momentum distributions were extracted for all excitation energy regions. The longitudinal and transverse response functions were extracted using the Rosenbluth separation technique. The longitudinal and transverse nature of the cross-sections is described well by the cel prescription of the off-shell electron-nucleon cross-section. The results are compared to modern calculations for few-body nuclear systems. These measurements constitute part of an extensive program at MAMI to study the 3,4 He(e,e′p) reaction systematically over a wide range of kinematics.