Interacting boson models for $N∼Z$ nuclei Available to Purchase

This contribution discusses the use of boson models in the description of $N∼Z$ nuclei. A brief review is given of earlier attempts, initiated by Elliott and co-workers, to extend the interacting boson model of Arima and Iachello by the inclusion of neutron-proton s and d bosons with $T = 1$ (IBM-3) as well as $T = 0$ (IBM-4). It is argued that for the $N∼Z$ nuclei that are currently studied experimentally, a different approach is needed which invokes aligned neutron-proton pairs with angular momentum $J = 2j$ and isospin $T = 0.$ This claim is supported by an analysis of shell-model wave functions in terms of pair states. Results of this alternative version of the interacting boson model are compared with shell-model calculations in the $1g9/2$ shell.