We discuss the correlation of the spin-singlet two-neutron pair, the dineutron correlation, in the ground and excited $0^{+}$ states of ${}^8$He by using a method to describe the dineutron correlation in neutron-rich nuclei: the dineutron condensate wave function. The shell-model configuration and the dineutron configuration are mixed with each other in the ground state of ${}^8$He. We compare the ground state structure of ${}^8$He with that of ${}^6$He and suggest that the dineutron correlation is weaker in the ground state of ${}^8$He than in ${}^6$He. We also suggest the possibility of dineutron condensation in an excited $0^{+}$ state of ${}^8$He. In addition, we investigate the formation mechanism of the dineutron condensation in ${}^8$He by using a newly developed framework, the $\alpha$ and dineutron condensate wave function, and conclude that the attraction from the core is essential for the formation of the dineutron condensation.

• Received 19 May 2013

DOI:https://doi.org/10.1103/PhysRevC.88.034321