Inclusive Coulomb and nuclear breakup of neutron-rich Ne, Mg, and Si isotopes, N. Kobayashi, Tokyo Institute of Technology, Japan − One-neutron removal cross sections of 29,31Ne, 33,35,37Mg, and 39,41Si on Pb target were measured at about 240 MeV/nucleon at RIBF(RI-Beam Factory) at RIKEN.  This experiment aims at extracting the inclusive Coulomb breakup cross sections of these nuclei to see if these nuclei can involve halo structures.  The enhancement of low-energy E1 strength, called "soft E1 excitation", is a unique property of halo nuclei.  Hence, the enhancement of Coulomb breakup cross section can be used as a direct signal for halo structures.  The result indeed showed a significant enhancement of the Coulomb breakup cross section for 31Ne and systematic enhancements for 37Mg and 41Si along isotopic chains.  This result thus shows the occurrence of soft E1 excitations, which suggests the one-neutron halo structure for 31Ne and the contributions of the one-neutron halo characters for 37Mg and 41Si.

 

In addition, the nuclear breakup cross sections of 29,31Ne, 33,35,37Mg, and 39,41Si and the parallel momentum distributions of 28,30Ne, 32,34,36Mg, and 38,40Si nuclei following one-neutron removal reactions on C target were measured.  The combined analysis of the Coulomb and nuclear breakup cross sections are used to determine the configuration of these nuclei.  The parallel momentum distributions of these nuclei also offer further information on the configuration. We discuss the shell structures near the island of inversion.