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arXiv · 2201.05731

Erosion of N = 28 shell closure: Shape coexistence and monopole transition

Y. Suzuki·W. Horiuchi·M. Kimura
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Abstract

Background: In neutron-rich nuclei neighboring 42Si, the quenching of the N = 28 shell gap occurs and is expected to induce the shape coexistence in their excitation spectra. Purpose: We show that different nuclear shapes coexist in N = 28 isotones 40Mg, 42Si, and 44S, and investigate observables to probe it. Method: Antisymmetrized molecular dynamics with Gogny D1S density functional is applied to describe the shape coexistence phenomena without ad hoc assumption of the nuclear shape. Results: We find that rigid shapes with different deformations coexist in the ground and the first excited 0+ states of 40Mg and 42Si, while in 44S the states exhibit large-amplitude collective motion, which does not have any particular shape. These characteristics are reflected well in the monopole transition strengths. Conclusion: The quenching of the N = 28 shell gap leads to the unique shape coexistence in the N = 28 isotones, which can be probed by the monopole transition strengths.

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Y. Suzuki, W. Horiuchi, M. Kimura. 2022-01-15. Erosion of N = 28 shell closure: Shape coexistence and monopole transition. https://arxiv.org/abs/2201.05731

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