Quasielastic knockout of clusters by fast protons at large momentum transfers and nuclear structure

Present ideas about nucleon clustering in nuclei are reviewed. The main attention is devoted to the role of excited clusters in the ground states of 1p-shell nuclei. Their properties, their status outside the framework of the translationally invariant shell model, and the conditions most favorable for manifestation of their contribution to nuclear reaction cross sections are discussed. It is shown that in (p, Nx) quasielastic knockout reactions the contribution of excited clusters, x*, may be the most important at large momentum transfer. The results are given of calculation of the characteristics of quasielastic knockout of d, t, and ..cap alpha.. particles at energies around 0.7 GeV at momentum transfer 5--10 F/sup -1/ with allowance for processes that take place on excited clusters, px*..-->..Nx, which are treated on the basis of existing ideas about the mechanisms of proton backward elastic scattering by the lightest nuclei in the corresponding range of energies.