Final-state-exclusive momentum distributions of fast, forward-traveling residual nuclei, following two-nucleon removal from fast secondary radioactive beams of projectile nuclei, can and have now been measured. Assuming that the most important reaction mechanism is the sudden direct removal of a pair of nucleons from a set of relatively simple, active shell-model orbital configurations, such distributions were predicted to depend strongly on the total angular momentum $I$ carried by the two nucleons—the final-state spin for spin $0^{+}$ projectiles. The sensitivity of these now-accessible observables to specific details of the (correlated) two-nucleon wave functions is of importance. We clarify that it is the total orbital angular momentum $L$ of the two nucleons that is the primary factor in determining the shapes and widths of the calculated momentum distributions. It follows that, with accurate measurements, this dependence upon the $L$ makeup of the two-nucleon wave functions could be used to assess the accuracy of (shell- or many-body-) model predictions of these two-nucleon configurations. By using several tailored examples, with specific combinations of active two-nucleon orbitals, we demonstrate that more-subtle structure aspects may be observed, allowing such reactions to probe and/or confirm the details of theoretical model wave functions.

• Received 25 July 2010

DOI:https://doi.org/10.1103/PhysRevC.82.044616