Speaker
Description
Study of isolated multi-neutron systems is one of fundamental subjects in nuclear physics. In several decades, experimental attempts have made with a particular focus on the tetra-neutron system. Among them, two experiments, the double-charge exchange reaction on ${}^4$He and the alpha-particle knockout reaction from the ${}^8$He, show a sharp peak structure just above the threshold in the four-neutron spectra, which could be a signature of a strong correlated state. Both the experiments have been realized by using the ${}^8$He beam above 150 A MeV at the RIKEN RI Beam Factory. Production mechanisms with kinematical considerations are introduced, where impulse natures and amount of the transferred energies and momenta of the reactions are emphasized. The relevant reaction processes are discussed and corresponding analysis procedures on the four-body continuum system taking into account the final-state interactions in the di-neutrons are presented.
