Probing the shape evolution and shell structures in neutron-rich N=50 nuclei

Fuente: arXiv
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Main Authors: Kumar, Anil, Shimizu, Noritaka, Miyagi, Takayuki, Tsunoda, Yusuke, Utsuno, Yutaka
Format: Preprint
Published: 2025
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_version_ 1866917026750005248
author Kumar, Anil
Shimizu, Noritaka
Miyagi, Takayuki
Tsunoda, Yusuke
Utsuno, Yutaka
author_facet Kumar, Anil
Shimizu, Noritaka
Miyagi, Takayuki
Tsunoda, Yusuke
Utsuno, Yutaka
contents The structure of low-lying states of $N=50$ nuclei is investigated by the advanced Monte Carlo shell model (MCSM) in the $π{(fp)}$-$ν{(sdg)}$ model space. We have employed the shell-model Hamiltonian based on the valence-space in-medium similarity renormalization group, with minimal phenomenological adjustments to the single-particle energies. The MCSM results with the modified Hamiltonian nicely predict the shape coexistence of $^{78}$Ni, consistent with recent experimental data. The evolution of intrinsic shapes from the spherical shape to prolate shapes in the ground state of $N=50$ nuclei is discussed using the "T-plot" and effective single-particle energies, which visualize the intrinsic quadrupole deformation of the MCSM wave function. The present result shows that the monopole part of the tensor force does not enhance the shape coexistence of $^{78}$Ni, unlike the case of $^{68}$Ni.
format Preprint
id arxiv_https___arxiv_org_abs_2510_16775
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Probing the shape evolution and shell structures in neutron-rich N=50 nuclei
Kumar, Anil
Shimizu, Noritaka
Miyagi, Takayuki
Tsunoda, Yusuke
Utsuno, Yutaka
Nuclear Theory
Nuclear Experiment
The structure of low-lying states of $N=50$ nuclei is investigated by the advanced Monte Carlo shell model (MCSM) in the $π{(fp)}$-$ν{(sdg)}$ model space. We have employed the shell-model Hamiltonian based on the valence-space in-medium similarity renormalization group, with minimal phenomenological adjustments to the single-particle energies. The MCSM results with the modified Hamiltonian nicely predict the shape coexistence of $^{78}$Ni, consistent with recent experimental data. The evolution of intrinsic shapes from the spherical shape to prolate shapes in the ground state of $N=50$ nuclei is discussed using the "T-plot" and effective single-particle energies, which visualize the intrinsic quadrupole deformation of the MCSM wave function. The present result shows that the monopole part of the tensor force does not enhance the shape coexistence of $^{78}$Ni, unlike the case of $^{68}$Ni.
title Probing the shape evolution and shell structures in neutron-rich N=50 nuclei
topic Nuclear Theory
Nuclear Experiment
url https://arxiv.org/abs/2510.16775