Speaker
Dr
Nicolas Schunck
(Universidad Autonoma de Madrid)
Description
With the recent advent of Radioactive Ion Beams facilities, entire regions of the
nuclear chart have become accessible in experiments. Moreover, the on-going
developments of e.g. new generations of segmented gamma arrays will also allow to
explore low-statistic reaction channels. This large and constant supply of new data
puts severe constraints on nuclear models. In particular, the shape and geometrical
symmetries of atomic nuclei are very sensitive to variations of the particle number
(going to the drip-lines), angular momentum (high-spin physics) or temperature (hot
nuclei). The nuclear shape is therefore a convenient tool to investigate the
underlying mechanisms that govern nuclear stability.
I will describe two phenomena to illustrate this point. On the one hand, nuclear
states corresponding to a shape with tetrahedral symmetry have been investigated in
the framework of various mean-field approaches, where it is interpreted as a
manifestation of the spontaneous symmetry breaking. The challenge, both for theorists
and experimentalists, now resides in the observation of the signatures of such
states. On the other hand, nuclear hyper-deformed states have been predicted for some
time, but it is only recently that the importance of the Jacobi transition in the
population of such states was recognized. Hyperdefomation represents a rare case of a
nucleus at the limit of deformation and spin, and thus is invaluable for theorists.
The experimental challenge consists in being able to populate such a weakly-populated
channel. I will conclude by mentionning some of the directions explored by theorists
to address such issues.
Author
Dr
Nicolas Schunck
(Universidad Autonoma de Madrid)
