Direct and Resonance Capture Reactions with Nucleons and Composite Particles

Abstract

What I’d like to do in this paper is primarily to discuss radiative proton capture measurements and direct-semidirect model calculations in both light and heavy nuclei. These are measurements in the giant-resonance region, and are of interest primarily in the degree to which they provide information on giant-quadrupole resonances, and on details of the giant-dipole resonance. Of course, in order to extract giant resonance information from radiative capture, one must first understand the reaction mechanism. To this end, I’ve made extensive investigations of the usefulness of the Direct-Semidirect (DSD) model,¹ and I’d like to illustrate for you both its spectacular successes and puzzling failures. I have a few brief comments to make about a-capture in light nuclei, and on neutron capture. Finally I’d like to discuss some exciting recent results on magnetic-dipole strength in the doubly-magic ¹⁶0 nucleus. Although most of what I’ll talk about generally falls-outside of what one generally calls “neutron physics”, it appropriately falls under the “Related Topics” section of this conference since much of this work bears significantly on fast-neutron capture physics, particularly the DSD calculations. Also, since I hope to present a discussion of rather wide scope (I hesitate to call it a review to avoid offending those whose work I fail to mention) I have taken the liberty of including some previously published work.