Large-scale shell-model calculations on the spectroscopy of $N<126$ Pb isotopes

TL;DR

This paper presents large-scale shell-model calculations for neutron-deficient lead isotopes, achieving good agreement with experimental data and providing insights into nuclear structure and electromagnetic properties.

Contribution

It introduces an optimized effective interaction and combines full shell-model, importance-truncation, and approximation methods to study Pb isotopes below N=126.

Findings

Good agreement with experimental excitation energies and electromagnetic properties.

Effective interaction successfully models spherical states in isotopes 194-206Pb.

Deviations highlight areas for understanding nuclear deformation.

Abstract

Large-scale shell-model calculations are carried out in the model space including neutron-hole orbitals $2p_{1/2}$, $1f_{5/2}$, $2p_{3/2}$, $0i_{13/2}$, $1f_{7/2}$ and $0h_{9/2}$ to study the structure and electromagnetic properties of neutron deficient Pb isotopes. An optimized effective interaction is used. Good agreement between full shell-model calculations and experimental data is obtained for the spherical states in isotopes $^{194-206}$Pb. The lighter isotopes are calculated with an importance-truncation approach constructed based on the monopole Hamiltonian. The full shell-model results also agree well with our generalized seniority and nucleon-pair-approximation truncation calculations. The deviations between theory and experiment concerning the excitation energies and electromagnetic properties of low-lying $0^+$ and $2^+$ excited states and isomeric states may provide a constraint on our understanding of nuclear deformation and intruder configuration in this region.