Neutron-proton halo structure of the 3.563-MeV0+state inLi6

We explore the possibility that a stable nucleus has halolike structure in high isospin excited states. As an example the structure of the 3.563 MeV $0^{+}$ state of ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ is studied in a fully microscopic α+p+n three-cluster model, because it is an isobaric analog state of ${}_{}{}^6{}_{}{}^{}\mathrm{He}$ with two-neutron halo structure. An extensive calculation with isospin mixing has shown that the state has spatially extended halolike structure formed by the neutron and the proton outside the α particle. Electron scattering form factors related with the state are reproduced fairly well.