High-j single-particle neutron states outside the N=82 core

TL;DR

This study investigates the behavior of specific single-neutron states outside the N=82 core using transfer reactions, revealing systematic energy shifts influenced by tensor interactions and state mixing in N=83 nuclei.

Contribution

It provides new experimental data on single-neutron state energies and mixing effects, confirming theoretical predictions about tensor interaction influences.

Findings

Measured energy shifts of i13/2 and h9/2 states with changing proton number

Observed mixing between l=5 and 6 strength states

Found constant mixing matrix elements across nuclei

Abstract

The behaviour of the i13/2 and h9/2 single-neutron strength was studied with the (4He,3He) reaction on 138Ba, 140Ce, 142Nd and 144Sm targets at a beam energy of 51 MeV. The separation between the single-neutron states i13/2 and h9/2 was measured in N =83 nuclei with changing proton number. To this end spectroscopic factors for states populated in high-l transfer were extracted from the data. Some mixing of l=5 and 6 strength was observed with states that are formed by coupling the f7/2 state to the 2+ and 3- vibrational states and the mixing matrix elements were found to be remarkably constant. The centroids of the strength indicate a systematic change in the energies of the i13/2 and h9/2 single-neutron states with increasing proton number that is in quantitative agreement with the effects expected from the tensor interaction.