Direct reaction probes of single-particle states and correlations

The most exotic neutron-proton asymmetric nuclei are produced most efficiently in high-energy fragmentation reactions. These exotic nuclei are produced as fast secondary beams with energies of order 100 MeV per nucleon or greater, and hence v/c > 0.3, often with relatively low intensities. For such beams one can exploit both the detection efficiency and the cross sections for fast oneand two-nucleon removal reactions. The reaction dynamics of these channels is relatively simple due to the fast (sudden), surface grazing, and forward travelling (eikonal) nature of the reaction mechanism. More recent work now interfaces these sudden, eikonal reaction models with more microscopic nuclear structure model input. The possible roles of nucleon and pair correlations and their observation using such reaction data are discussed.