Yuma Kikuchi

Recent development of complex scaling method for many-body resonances and continua in light nuclei

Abstract The complex scaling method (CSM) is a useful similarity transformation of the Schrodinger equation, in which bound-state spectra are not changed but continuum spectra are separated into resonant and non-resonant continuum ones. Because the asymptotic wave functions of the separated resonant states are regularized by the CSM, many-body resonances can be obtained by solving an eigenvalue problem with the L 2 basis functions. Applying this method to a system consisting of a core and valence nucleons, we investigate many-body resonant states in weakly bound nuclei very far from the stability lines. Non-resonant continuum states are also obtained with the discretized eigenvalues on the rotated branch cuts. Using these complex eigenvalues and eigenstates in CSM, we construct the extended completeness relations and Green’s functions to calculate strength functions and breakup cross sections. Various kinds of theoretical calculations and comparisons with experimental data are presented.

Systematic Study of 9,10,11Li with the Tensor and Pairing Correlations

We make a systematic study of Li isotopes (A=9,10,11) in the tensor optimized shell model for 9Li and treat the additional valence neutrons in the cluster model approach by taking into account the Pauli-blocking effect caused by the tensor and pairing correlations. We describe the tensor correlations in 9Li fully in the tensor-optimized shell model, where the variation of the size parameters of the single particle orbits is essential for getting strong tensor correlations. We have shown in our previous study that in

Coulomb Breakup Reactions in Complex-Scaled Solutions of the Lippmann-Schwinger Equation

^{10,11}

Coulomb breakup reactions of Li-11 in the coupled-channel Li-9 + n + n model

Li the tensor and pairing correlations in 9Li are Pauli-blocked by additional valence neutrons, which make the p-shell configurations pushed up in energy. As a result, the

Five-body resonances of 8C using the complex scaling method

s^2

Four-body resonances of 7B using the complex scaling method

valence neutron component increases to reveal the halo structure of 11Li and the inversion phenomenon of the single particle spectrum in 10Li arises. Following the previous study, we demonstrate the reliability of our framework by performing a detailed systematic analysis of the structures of

Two neutron decay from the 21+ state of 6He

^{9,10,11}

Photodisintegration cross section of 9Be up to 16 MeV in the α + α + n three-body model

Li, such as the charge radius, the spatial correlation of halo neutrons of 11Li and the electromagnetic properties of Li isotopes. The detailed effects of the Pauli-blocking on the spectroscopic properties of

Coulomb breakup reactions of 11Li in the coupled-channel 9Li+n+n model

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Photodisintegration cross section ofBe9up to 16 MeV in theα + α + nthree-body model

Li are also discussed. It is found that the blocking acts strongly for the 11Li ground state rather than for 10Li and for the dipole excited states of 11Li, which is mainly caused by the interplay between the tensor correlation in 9Li and the halo neutrons. The results obtained in these analyses clearly show that the inert core assumption of 9Li is not realistic to explain the anomalous structures observed in