Reinvestigation of the excited states in the proton emitter $^{151}$Lu: particle-hole excitations across the $N=Z=64$ subshell

TL;DR

This study revises the excited state level scheme of the proton emitter $^{151}$Lu through experimental measurements and shell model calculations, revealing the influence of particle-hole excitations across the $N=Z=64$ subshell.

Contribution

It provides new experimental data and theoretical insights into the excited states of $^{151}$Lu, highlighting particle-hole excitations across the $N=Z=64$ subshell for the first time.

Findings

Updated level scheme with five new gamma-ray transitions.

Excitation energies are sensitive to particle-hole excitations.

Shell model calculations support the experimental observations.

Abstract

The excited states of the proton emitter $^{151}$Lu were reinvestigated in a recoil-decay tagging experiment at the Accelerator Laboratory of the University of Jyv\"askyl\"a (JYFL). The level scheme built on the ground state of $^{151}$Lu was updated with five new $\gamma$-ray transitions. Large-scale shell model calculations were carried out to interpret the experimental level scheme. It is found that the excitation energies of states above the $27/2^-$ and $23/2^+$ isomeric levels can be sensitive to excitations from $g_{7/2}$ and $d_{5/2}$ to single-particle orbitals above $N=Z=64$.