High-spin state spectroscopy with the polarized (d vector, α) and (p vector, π) reactions

This report deals with two research areas. The first involves high-spin state spectroscopic studies with the two nucleon pickup A(d, α)A-2 reaction, while the second topic is that of nuclear pion production A(p, π)A + 1 near threshold. Both studies are successful in part because of the strategic use of polarized beams and measurement of the resulting polarization observables. It is insisted that the (d, α) reaction at moderate bombarding energies is indeed a powerful spectroscopic tool. Characteristic Ltrans and Jtrans signatures are developed and used to map out high-spin strength in several f7/2-shell nuclei for comparison with modern shell model calculations. For pions, a heuristic approach is taken to the general concept of a two-nucleon model for near-threshold pion production - the many features, which either emerge or are predicted, have a quantitative explanation in terms of underlying NN → NNπ processes 'immersed' in the nuclear medium. The fact that these experimental TNM signatures have such a simple interpretation probably means that the fundamental NN → NNπ amplitudes are rather stable in thir off-shell behavior. Discussion is also made about how and why (p, π-) transitions are relatively weak, highly constrained, and often very selective. (Nogami, K.)