Relativistic eikonal approximation in high-energy A (e,e ' p) reactions - art. no. 024611

A fully relativistic model for the description of exclusive (e,e'p) reactio ns off nuclear targets at high energies and momentum transfers is outlined. It is based on the eikonal approximation for the ejectile scattering wave function and a relativistic mean-field approximation to the Walecka model. Results for C-12(e,e'p) and O-16(e,e'p) differential cross sections and sep arated structure functions are presented for four-momenta in the range 0.8 less than or equal to Q(2) less than or equal to 20 (GeV/c)(2). The regions of applicability of the eikonal approximation are studied and observed to be confined to proton knockout in a relatively small cone about the momentu m transfer. A simple criterion defining the boundaries of this cone is dete rmined. The Q(2) evolution of the effect of off-shell ambiguities on the di fferent (e,e'p) structure functions is addressed. At sufficiently high valu es of Q(2) their impact on the cross sections is illustrated to become prac tically negligible. It is pointed out that for the whole range of Q(2) valu es studied here, the bulk of the relativistic effects arising from the coup ling between the lower components in the wave functions, is manifesting its elf in the longitudinal-transverse interference term.