ANGULAR-DISTRIBUTIONS FOR KNOCKOUT AND SCATTERING OF PROTONS IN THE EIKONAL APPROXIMATION

The advent of new electron accelerators with few-GeV beam energies mak es the (e,e'p) reaction a promising tool for investigating new aspects of the electromagnetic interaction. To this purpose it is crucial to set the scale of final-state interactions (FSI) at high ejectile energ ies. Usually, the problem is faced by mutuating well-established resul ts of the Glauber method in the framework of elastic (p,p) scattering. Since the generalization of this eikonal approximation to the (e,e'p) case is not straightforward, we have analyzed the constraints which m ake the comparison a meaningful one, using the C-12(e,e'p)B-11(s1/2) a nd B-11(s1/2)(p,p) reactions with outgoing-proton momenta of 4 GeV/c a s a test case. The FSI dominance at large deflection angles produces i n the distributions a universal behavior resembling the coherent diffr active scattering between the ejected proton and the (residual) nucleu s. Because of the selected sensitivity of the (e,e'p) distribution to different theoretical ingredients depending on different values of the deflection angle (or transverse missing momentum), it is argued that the previous comparison with elastic proton scattering may represent a convenient tool to disentangle effects due to the (hard) electromagne tic vertex from (exotic) effects related to the propagation of the str uck hadron through the nuclear medium.