Isospin Splitting of the Giant Dipole Resonance, and Muon Capture

The correspondence between the upper fragment of the split electromagnetic giant dipole resonance and the parent dipole mode excited by muon capture is investigated for nuclei with a neutron excess. Results already found for light ($N=Z$) nuclei are extended to heavier ($N>Z$) nuclei, suggesting new types of experiments to demonstrate the isospin origin of this splitting.