Related papers: $\alpha+{}^2n+{}^2n$ 3-body cluster structures and…
The hyper-radial barrier strongly hinders formation of more than three clusters. We investigate how well the dominating cluster components in $^7$He and $^8$He, respectively can be described as $\alpha$+$n$+$^2n$ and $\alpha$+$^2n$+$^2n$,…
The ground and excited states of $^{8}$He were investigated with a method of antisymmetrized molecular dynamics(AMD). We adopted effective nuclear interactions which systematically reproduce the binding energies of $^4$He, $^6$He and…
Background: The four-neutron correlation has been attracting much attention for decades. In addition to the study on the tetra-neutron system, it is worthwhile to investigate the correlation in bound systems. Purpose: The $^8$He nucleus is…
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…
Cluster structures of excited $^{10}$Be states are investigated with a hybrid model of dineutron condensate wave functions and $^6$He+$\alpha$ cluster wave functions. Two kinds of cluster states are theoretically suggested a few MeV above…
The four nucleons in $^8$Li outside the $\alpha$-particle ($\alpha=^4$He) can be divided into pairs of one neutron ($n$) and 3 nucleons in the triton ($t=^3$H), or 2 in the deuteron ($d=^2$H) and two neutrons in a dineutron ($^2n$). The…
Recent experiments clearly demonstrate the importance of the excited state $2^+$ at 1.8 MeV in the substruture ${^6}He$ for the ground state of the nucleus ${^8}He$. It is shown here that this means that the ground state structure of…
We investigate the multineutron excitations of neutron-rich $^8$He in the electric dipole strength using a $^4$He+$n$+$n$+$n$+$n$ five-body model. Many-body unbound states of $^8$He are obtained in the complex scaling method. We found that…
The structure of $^8$He is investigated within a three-cluster microscopic model. The three-cluster configuration $\alpha+^2n+^2n$ was used to describe the properties of the ground state of the nucleus. The obtained results evidently…
The structure of neutron-rich $\Lambda$ hypernucleus, $^7_{\Lambda}$He is studied within the framework of an $\alpha +\Lambda +n+n$ four-body cluster model. We predict second $3/2^+$ and $5/2^+$ states, corresponding to a $0s$ $\Lambda$…
The 0+ states of 8He are studied in a five-body 4He+n+n+n+n cluster model. Many-body resonances are treated on the correct boundary condition as Gamow states using the complex scaling method. The 0+_2 state of 8He is predicted as a…
We realize the treatment of bound and continuum nuclear systems in the proximity of a three-body breakup threshold within the ab initio framework of the no-core shell model with continuum. Many-body eigenstates obtained from the…
The structure of $1/2^{\pm}$ states in $^{13}$C up to around the $3\alpha+n$ threshold ($E_x = 12.3$~MeV) is investigated with a full four-body $3\alpha+n$ orthogonality condition model (OCM) calculation, where the $3\alpha$ OCM, the model…
Low-energy dipole excitations in ${}^{10}$Be were investigated based on the generator coordinate method with $\alpha + {}^6$He and $\alpha + \alpha + 2n$ cluster models. We obtained three $1^-$ states in $E_{x} < 15$~MeV, which show…
We introduce a new model applying to the core-nucleus and two-neutron system. The Faddeev equations of 6He-n-n and 8He-n-n systems for 8He and 10He are solved, respectively. The potential of the subsystem in the model has been determined to…
We study the $\alpha + \alpha + {}^{3}$He cluster structure of ${}^{11}$C within the microscopic cluster model. The calculations essentially reproduce the energy spectra for both negative and positive parity states, particularly the…
The cluster $^4\rm He+\Lambda+\rm n$ model is applied to describe the $^6_\Lambda$He hypernucleus. The consideration is based on the configuration space Faddeev equations for a system of non-identical particles. A set of the pair potentials…
We calculated the energy spectra of the neutron-rich He $\Lambda$ hypernuclei with $A=6$ to 9 within the framework of an $\alpha + \Lambda +Xn$ ($X=1$--4) cluster model using the cluster orbital shell model. The employed constituent…
Excited states of $^4$He are studied in four-body calculations with explicitly correlated Gaussian bases. All the levels below $E_{\rm x}$=26 MeV are reproduced reasonably well using realistic potentials. An analysis is made to show how the…
Two new low-lying $^6$He levels at excitation energies of about 2.4 and 2.9 MeV were observed in the experimental investigation of the p-$\alpha$ coincidence spectra obtained by the $^3$H($^4$He,p$\alpha$)2n four-body reaction at $E_{\rm…