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

Structure within the N=40 Island of Inversion

Not scheduled

20m

Main Lecture Hall (University of Aizu)

Speaker

Heather Crawford (Lawrence Berkeley National Laboratory)

Description

The focus of this work is neutron-rich Fe and Mn isotopes with N~40, which lie within an Island of Inversion approximately centered at ⁶⁴Cr. Here, a quenching of the N=40 sub-shell gap allows multi-particle multi-hole excitations and deformation to develop in the ground-state configurations of nuclei in the region. Limited spectroscopic information has been collected so far in the region of N~40 below ⁶⁸Ni. For the even-even nuclei, the 2⁺₁ and 4⁺₁ state energy systematics has been explored and, for the Fe and Cr isotopes, of B(E2; 2⁺₁->0⁺₁) values have been measured up to ⁶⁸Fe and ⁶⁴Cr. Large-scale shell model (LSSM) calculations well reproduce the energy systematics of the observed low-lying states of the even-even Fe and Cr isotopes around N=40. However, spectroscopic factor and more complete level scheme predictions in the region have not yet been benchmarked by experimental results.
Proton knockout reactions on the neutron-rich N=38 and N=40 isotopes ^64,66Fe and ^63,65Mn have been performed to investigate the proton spectroscopic factors of the parent nuclei. We will discuss the results of this measurement as well as a complementary secondary fragmentation measurement, and interpret in comparison with both LSSM and Nilsson model calculations.