Ne and its halo structure

It is well known that N=20 shell gap disappears in the "island of inversion." The one-neutron halo nucleus ³¹Ne, located in the island of inversion, has attracted much attention because it is the first example of a deformation-driven halo nucleus.

Recent experimental studies on ³¹Ne revealed that it has low separation energy Sn=0.15^(+0.16)_(-0.10) MeV, spectroscopic factor C²S=0.32^(+0.21)_(-0.17), and ground-state spin and parity 3/2^-. This results show that ³¹Ne is significant p-wave halo component.

We have carried out the exclusive Coulomb breakup measurement of ³¹Ne for the first time using the invariant mass method. The new data enables us to determine the neutron separation energy and spectroscopic factor more precisely than the values determined by the inclusive Coulomb breakup measurement.

Coulomb breakup measurement using ³¹Ne beam at 230 MeV/u with a lead target was performed using SAMURAI spectrometer at RIBF, RIKEN.

In this presentation, the experimental results will be discussed.