The Investigation of Hole States in Nuclei by Means of Knockout and Related Reactions

Abstract

There is a wide variety of reactions which can give rise to the excitation of hole states; for example, pickup and knockout caused by many different projectiles, photodisintegration, kaon capture, and pion absorption. Some of these reactions occur through different mechanisms, some occur through the same mechanism but involve very different regions of momentum transfer or have different degrees and areas of spatial localization, but all give information about nuclear structure in essentially the same way. When a single nucleon or group of nucleons is removed from a nucleus, by whatever means, information is obtained about its wave function in the nucleus and the hole state created by its removal. The hole state created by the removal of these nucleons is not, in general, an eigenstate of the residual nucleus, but the hole strength is distributed over several states of the residual nucleus. The amount of hole strength each particular final state contains is measured in terms of the spectroscopic factors and comparison with the experimental spectroscopic factors gives information about the parentage of the target nucleus and the relevance, or otherwise, of various nuclear models (MF 60, Mac 64).