Magic or Superfluid?

2024/08/26

The neutron-rich unbound fluorine isotope 30F has been observed for the first time in an experiment at the SAMURAI spectrometer at the RIBF in RIKEN, Japan. The measured neutron separation energy shows no sharp decrease after N=20 providing the most direct confirmation that the N=20 shell gap is not restored in this region of the chart of nuclides close to 28O (see also our recent article on the discovery of 28O, Nature 620 (2023) 965). This result published in Physical Review Letters 133 (2024) 082501 also suggests a 2-neutron halo character of 31F.