The virtual-state character of the 9ᵇe 1/2+ state in the 9ᵇe(γ,n)8ᵇe reaction

الأصل · EN

We study the character of the first excited 1/2⁺ state of 9ᵇe, which is observed as a low-lying sharp peak in the cross section of 9ᵇe(γ,n)2α just above the 8ᵇe+n threshold. Using the α+α+n three-body model, we describe the ground and excited unbound states of 9ᵇe above the α+α+n threshold. Applying the complex scaling method to the three-body model, we find no 1/2⁺ resonant solutions, while the low-lying peak in the photodisintegration cross section is reproduced in the present calculation. It is found that the low-lying peak is dominantly explained by the 8ᵇe+n component. Furthermore, using the analytical continuation of the coupling constant of the three-body interaction for the α+α+n system, we discuss the virtual-state character of the 1/2⁺ state.