34Si ; a bubble nucleus to probe the spin-orbit interaction and the nuclear matter incompressibility ?
By O. Sorlin - GANIL
A bubble nucleus displays a reduced nuclear density in the center. I will first describe where such nuclei can be found in the chart of nucleus, and for which reason(s). Apart from the case of 34Si, attention will be also be given to superheavy nuclei in which the repulsion between protons naturally favors a central density depletion. In a second step I will show how to use a bubble nucleus, such as 34Si, to check the validity of the spin orbit interaction, as postulated 60 years ago or as used commonly in Mean Field or Relativistic Mean Field calculations. The main assets of this nucleus is to give access to the density and isospin dependent parts of the SO interactions, which were never tested so far. These two aspects have however direct impacts on the spin orbit interaction (and hereby on shell gaps) at the drip line, and on the location of a possible island of stability in super heavy nuclei. Based on the experimental results obtained in the thesis of G. Burgunder, I will propose tracks to explore with respect to the evolution of shells and magic nuclei, which sensibly depend on the spin orbit interaction. Finally, I will present a very preliminary idea to use bubble nuclei to probe the nuclear matter incompressibility at about half the saturation density.