Single-particle and collective motions from nuclear many-body correlation (PCM2025)

Quadrupole collectivity in low-lying states in neutron-rich N=40 nuclei

4 Mar 2025, 17:00

20m

Main Lecture Hall (University of Aizu)

Session #4

Speaker

Kouhei Washiyama (University of Tsukuba)

Description

Recent spectroscopic measurements in neutron-rich $N=40$ nuclei towards ${}^{60}$Ca give an insight into shell structure in this region [1]. Large-scale shell model calculations [2] predicted a sizable collectivity in ${}^{60}$Ca and the island of inversion extended to ${}^{60}$Ca.
In this contribution, we will present the results of low-lying states in $N=40$ nuclei by employing the five-dimensional collective Hamiltonian (5DCH) method based on the Skyrme energy density functional. The 5DCH method explicitly treats quadupole degrees of freedom for rotation and vibration. We use the local quasiparticle random phase approximation to include important dynamical correlations to the inertial functions in the kinetic energies that have been ignored in most of the previous related works [3]. The present calculation reproduces the experimental $2_1^{+}$ energy and $B(E2;2_1^{+}\to 0_1^{+})$ values. In particular, we discuss the property of the low-lying excited $0^{+}$ state and low $R_{0/2}=E(0_2^{+})/E(2_1^{+})$ ratio obtained in ${}^{60}$Ca.
[1] M. L. Cortes et al., Phys. Lett. B 800, 135071 (2020).
[2] S. M. Lenzi, F. Nowacki, A. Poves, and K. Sieja, Phys. Rev. C 82, 054301 (2010).
[3] K. Washiyama, N. Hinohara, and T. Nakatsukasa, Phys. Rev. C 109, L051301 (2024).

Presentation materials

washiyamaPCM2025 - Kouhei Washiyama.pdf