The Halo Nucleus 14{sup left}Be and the unbound nucleus 13{sup left}Be

摘要

The one neutron removal from a secondary beam of 14{sup left}Be at 35MeV/A, produced at the LISE3 spectrometer, GANIL, has been used to study the near-threshold structure of the unbound nucleus 13{sup left}Be. The relative energy in the 12{sup left}Be + n system has been reconstructed and suggests significant s-wave strength in addition to a previously suggested d-wave resonance at around 2MeV. The momentum distribution of the reconstructed 13{sup left}Be, parallel to the beam direction, consists of at least two components and requires the inclusion of d-wave strength in the single-particle structure of 14{sup left}Be, although it does not rule out the inclusion of p-wave strength.