One-neutron removal strength of 7He into 6He using the complex scaling method

We study the one-neutron removal strength of the 7He ground state, which provides us with the 6He-n component in 7He. The He isotopes are described on the basis of the 4He+Xn cluster model (X=1,2,3). The complex scaling method is applied to describe not only the Gamow resonances but also the nonresonant continuum states of valence neutrons, with the correct boundary condition of particle decays. The one-neutron removal strength of 7He into the unbound states of 6He is calculated using the complex-scaled Green's function, in which a complex-scaled complete set of 4He+n+n states is adopted. Using this framework, we investigate resonant and nonresonant contributions of the strength, which individually produce specific structures in the distributions. In addition, we propose a method to obtain the real-value strength using the complex values of spectroscopic factors of Gamow states. As a result, the 6He(2+) resonance is found to give the largest contribution.