Title: Aligned neutron-proton pairs in N = Z nuclei

Speaker: Prof. Piet V. Isacker

Time and place: 12:30-13:00, March 27 (Wednesday), 2013, Lecture Hall/INPAC

Abstract:

The study of nuclei with equal numbers of neutrons and protons (N = Z) is one of the declared objectives of radioactive-ion-beam facilities. Currently, N = Z experiments are reaching 100Sn, involving studies of nuclei where nucleons are dominantly confined to the 1g9/2 orbit.

In this talk it is shown that the aligned neutron-proton pair with angular momentum J = 9 and isospin T = 0 plays a central role in the low-energy spectroscopy of the N ~ Z nuclei in this mass region. This observation is made by analyzing shell-model wave functions in terms of a variety of two-nucleon pairs with different angular momentum J and isospin T.

On the basis of these results one concludes that a simple model can be formulated in terms of isoscalar bosons with J = 9. Due to its simplicity, such a model could be of use to elucidate the main structural features of N ~ Z nuclei in this mass region. Examples of simple predictions resulting from this approach are discussed.