Abstract: | A basic assumption underlying the high-energy hadron-nucleus optical potential is that no target nucleon is struck more than once. Although this condition is satisfied at high energy, such is not the case in the vicinity of medium-energy resonances, where the amplitude for the projectile to undergo multiple reflections between two target nucleons is quite large. As a remedy for this problem, the multiple-scattering series is rearranged such that the optical potential can be expressed as a cluster expansion. The lowest order optical potential is modified by a two-body cluster term, which is a sum of all possible reflections of the projectile between a pair of target nucleons. This term is evaluated for a model potential within the formalism of Foldy and Walecka: it is substantially smaller than the contribution of a single reflection, and its overall effect is small under certain additional restrictions. If the independent-pair picture of nuclei is valid, then the three-body cluster term may be small, and the lowest order Glauber optical potential can provide a self-consistent picture of hadron-nucleus interactions, even though a term-by-term expansion of the multiple-scattering series does not provide such assurance. |