Coulomb and nuclear breakup reactions of a halo nucleus 31Ne

Experimental results on the exclusive Coulomb and nuclear breakup of ³¹Ne at c.a. 240 MeV/nucleon at RIBF at RIKEN are presented. The experiment used both C and Pb targets, and the emitted ³⁰Ne and the neutron were measured in coincidence using the SAMURAI spectrometer at RIBF. Gamma rays were also measured when ³⁰Ne was produced in any bound excited states. The extracted Coulomb breakup energy spectrum for the Pb target showed a strong peak just above the neutron decay threshold, typical for a halo nucleus, and is consistent with the previous inclusive measurements. A remarkable result was that the decay channel into the first excited state of the 30Ne core plus a neutron has significant cross sections. For the nuclear breakup of 31Ne, in addition to the 31Ne+C results, we also obtained the results for the one proton removal of 32Na and one neutron removal of 32Ne. Combined results have revealed several new resonance states above the one neutron decay threshold of 31Ne. The spectrum is discussed in terms of a deformed halo structure of the island-of-inversion nucleus 31Ne.