Laser spectroscopy near exotic doubly-magic nuclei to benchmark state-of-the art nuclear theories.

This project aims at measuring the properties of the cornerstones in
the nuclear chart: doubly-magic nuclei and their immediate
neighbors, in particular for those very far from stability (24O, 54Ca,
78Ni, 100Sn, 132Sn). Doubly-magic nuclei appear all over the
nuclear chart and those close to stability (16O, 40Ca and 48Ca, 56Ni
and 208Pb) have been studied in great detail and helped in
understanding the nuclear shell structure. Since exotic nuclei are
studied in more detail, it was observed that shell structure is not
static and depends on the proton-to-neutron ratio. Thus empirical
shell models are found to be not predictive. Since a few years,
modern nuclear theories are based on nucleon-nucleon potentials
derived from QCD using chiral effective field theory. A variety of
many-body methods is used to solve the nuclear problem, by fitting
their parameters to observables from light nuclei only! We aim to test
those theories at the extremes of the nuclear chart, in particular
around exotic doubly-magic isotopes which are the anchor points of
nuclear theories. We have developed very sensitive laser
spectroscopy methods that allow to measure several nuclear
properties in a single experiment: their spin, size and moments.
Developments in this project should allow to reach those isotopes for
the first time. Their observables will benchmark the predictive power
of nuclear models and provide information to test and improve them.