Effect of neutron halos on excited states of nuclei

Abstract

The differential cross sections of the inelastic scattering leading to the excitation of short-lived states in the stable ${}^{13}$C and ${}^{9}$Be nuclei as well as the radioactive ${}^{11}$Be nucleus have been analyzed. Signatures of neutron halos in the excited states located close to the neutron emission thresholds have been investigated by applying a recently developed modified diffraction model. The abnormally large rms radius was identified for the 3.089-MeV $1/{2}^{+}$ state of ${}^{13}$C. Significantly enlarged diffraction radii were found for the 1.68-MeV $1/{2}^{+}$ and the 3.05-MeV $5/{2}^{+}$ states of ${}^{9}$Be. The analysis of the diffraction radii of the weakly bound radioactive ${}^{11}$Be nuclei have shown that the 1.78-MeV $5/{2}^{+}$ and 3.41-MeV $3/{2}^{+}$ states in ${}^{11}$Be have the same diffraction radii as the $1/{2}^{+}$ ground state, which is known as the best example of a state with one-neutron halo.