arXiv subjects

Takayuki Myo

Publications and source records attributed to Takayuki Myo.

75 records · Page 5Linked to original sources

arXiv2005

Level Density in the Complex Scaling Method

It is shown that the continuum level density (CLD) at unbound energies can be calculated with the complex scaling method (CSM), in which the energy spectra of bound states, resonances and continuum states are obtained in terms of $L^2$ basis functions. In this method, the extended completeness relation is applied to the calculation of the Green functions, and the continuum-state part is approximately expressed in terms of discretized complex scaled continuum solutions. The obtained result is compared with the CLD calculated exactly from the scattering phase shift. The discretization in the CSM is shown to give a very good description of continuum states. We discuss how the scattering phase shifts can inversely be calculated from the discretized CLD using a basis function technique in the CSM.

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arXiv2005

Tensor correlation in 4He and its Effect on the doublet splitting in 5He

We investigate the role of tensor correlation on the structures of \nuc{4}{He} and its effect on the doublet splitting in \nuc{5}{He}. We perform a configuration mixing calculation in the shell model type bases to represent the tensor correlation for $^4$He. It is found that our model describes the characteristics of the tensor correlation, which is represented by an admixture of the $0s_{1/2}$ configuration with a spatially modified $0p_{1/2}$ orbit. For $^5$He, we solve a coupled OCM equation for an extended $^4$He+$n$ model, while taking into account the tensor correlation in the $^4$He cluster. It is shown that the tensor correlation produces the Pauli blocking, in particular, for the $J^π={1/2}^-$ state, and its effect causes about half of the p-wave doublet splitting in $^5$He. This indicates that the strength of the effective spin-orbit interaction should be reduced by about half from the conventional one. We obtain a reliable $^4$He-$n$ interaction, including the tensor correlation, which further improves the behavior of the $d$- and $f$-wave phase shifts in the $^4$He+$n$ system.

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arXiv2002

Extended 9Li+n+n three-body model of 11Li with the pairing correlation in 9Li

We discuss the binding mechanism of 11Li based on an extended three-body model of Li+n+n. In the model, we take into account the pairing correlation of p-shell neutrons in 9Li, in addition to that of valence neutrons outside the 9Li nucleus, and solve the coupled-channel two- and three-body problems of 10Li and 11Li, respectively. The results show that degrees of freedom of the pairing correlation in 9Li play an important role in the structure of 10Li and 11Li. In 10Li, the pairing correlation in 9Li produces a so-called pairing-blocking effect due to the presence of valence neutron, which degenerates s- and p-wave neutron orbits energetically. In 11Li, on the other hand, the pairing-blocking effect is surpassed by the core-n interaction due to two degrees of freedom of two valence neutrons surrounding 9Li, and as a result, the ground state is dominated by the p-shell closed configuration and does not show a spatial extension with a large r.m.s. radius. These results indicate that the pairing correlation is realized differently in odd- and even-neutron systems of 10Li and 11Li. We further improve the tail part of the 9Li-n interaction, which works well to reproduce the observed large r.m.s. radius in 11Li.

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