One-neutron knockout from light neutron-rich nuclei at relativistic energies

Abstract

One-neutron knockout reactions from neutron-rich nuclei, with $Z=6\ensuremath{-}13$ and $N=8\ensuremath{-}22$, were studied at the Fragment Separator (GSI) at high beam energies, around 700 MeV/nucleon. Structural phenomena such as the formation of one-neutron halos in odd-mass carbon isotopes ($^{15,17,19}\mathrm{C}$) will be discussed. In addition, one-neutron knockout measurements from $^{22}\mathrm{N}$ were carried out for the first time and demonstrate clearly the change from a $0{d}_{5/2}$ to a $1{s}_{1/2}$ orbital for the valence neutron, an effect that is expected above $N=14$ and that was also observed in $^{23}\mathrm{O}$ and $^{24}\mathrm{F}$. The possibility of an anomalous structure of $^{26}\mathrm{F}$, due to a significant $1{s}_{1/2}$ neutron admixture, will also be discussed in the light of the experimental data obtained in this work. Finally, the ground-state configuration of neutron-rich neon isotopes ($^{24\ensuremath{-}28}\mathrm{Ne}$) was studied, providing new information in a region that is relatively close to the island of inversion.