Team Investigates Quadrupole Collectivity Beyond N=28

In a recent paper published in Physical Review Letters, a team of NSCL physicists report on the first experimental study of quadrupole collectivity in the very neutron-rich nuclei 47,48Ar using intermediate-energy Coulomb excitation. Though the experimental results reveal that work still needs to be done for theoretical models to describe the very neutron-rich argon isotopes around N=28, the technique used in the experiment will be critical for future experiments using future facilities. The study was led by Ryan Winkler, a former NSCL postdoc now at Los Alamos National Lab.

In an accompanying Viewpoint, Paul Cottle and Kirby Kemper from Florida State University talk of the importance that the intermediate energy Coulomb excitation technique will have in exploring the neutron drip-line in the future. They write, “Altogether, the work on argon-47 and argon-48 pushes us a long way toward being prepared when FRIB and other radioactive beam facilities come online and the final spectroscopic assault on the neutron dripline for heavier elements begins.”

The paper - an Editors’ Suggestion - can be found at, while the accompanying Viewpoint can be found at