Variation in displacement energies due to isospin nonconserving forces

TL;DR

This paper investigates how isospin nonconserving nuclear forces affect displacement energies in mirror nuclei, showing they are significant in the f7/2 shell but not in the upper fp-shell, and predicts proton drip-line locations.

Contribution

It demonstrates the importance of isovector and isotensor forces in explaining displacement energies within the shell model for certain nuclei.

Findings

Displacement energies are well reproduced with isospin nonconserving forces in the f7/2 shell.

No evidence for these forces in the upper fp-shell.

Predicted proton drip-line locations based on the model.

Abstract

For mirror nuclei with masses A=42-95, the effects of isospin nonconserving nuclear forces are studied with nuclear shell model using the Coulomb displacement energy and triplet displacement energy as probes. It is shown that the characteristic behavior of the displacement energies can be well reproduced if the isovector and isotensor nuclear interactions with J=0 and T=1 are introduced into the f7/2 shell. These forces, with their strengths being found consistent with the nucleon-nucleon scattering data, tend to modify nuclear binding energies near the N=Z line. At present, no evidence is found that these forces are needed for the upper fp-shell. Theoretical one- and two-proton separation energies are predicted accordingly, and locations of the proton drip-line are thereby suggested.