Speaker
Description
Recently, a spectroscopic study in $^{62}$Ti has provided important information on nuclear structure approaching $^{60}$Ca [1]. A large-scale shell model calculation shows that the ground state of $^{60}$Ca has strong quadrupole collectivity, which suggests that $^{60}$Ca belongs to the so-called "island of inversion" at $N=40$ [2].
To study the quadrupole collectivity around $^{60}$Ca, we employ the so-called five-dimensional quadrupole collective Hamiltonian method based on density functional theory (DFT). In this method, the potential energy surface in the $\beta$-$\gamma$ plane is calculated using the constrained Skyrme Hartree-Fock-Bogoliubov (CHFB) method. The inertial functions in the kinetic energy terms are calculated using local quasiparticle random phase approximation (LQRPA) [3]. This method overcomes drawbacks of the so-called cranking formula that has been used in inertial functions in the former DFT-based collective Hamiltonian methods.
In this talk, we will present our results for the low-lying structure of neutron-rich $N = 40$ isotones, including $^{60}$Ca. Then, we will discuss an emergence of a new type of shape coexistence that we discovered in $^{60}$Ca. In particular, we will explain how the LQRPA inertial functions affect the first excited $0^+$ state and contribute to the emergence of shape coexistence.
[1] M. L. Cortes et al., Phys. Lett. B 800, 135071 (2020).
[2] S. M. Lenzi, F. Nowacki, A. Poves, K. Sieja, Phys. Rev. C 82, 054301 (2010).
[3] K. Washiyama, N. Hinohara, T. Nakatsukasa, Phys. Rev. C 109, L051301 (2024).
| Contribution category | Theory |
|---|---|
| Presenter status | Faculty/Staff |