The triple-differential cross sections for elastic breakup of 156-MeV ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ measured at larger relative momenta of the outgoing α-particle and deuteron fragments exhibit conspicuous double-peaked structures in the momentum-transfer dependence. The origin of these features is explored, sensitively revealing interference and off-shell scattering effects in the fragment-target interaction. Elastic breakup data of 56-MeV deuterons and 90-MeV ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ are reanalyzed in view of these effects on the basis of the prior-form distorted-wave Born-approximation theory.

• Received 8 March 1989

DOI:https://doi.org/10.1103/PhysRevLett.63.601