Isospin mixing during the decay of the giant dipole resonance

The magnitude of the isospin mixing in the initial 1p-1h doorway state and in the underlying compound states of the 28Si giant dipole resonance is estimated from (γ,p), (γ,α) and (γ,n) cross sections. From the mixing coefficients, mixing widths of about 40 keV and 25 keV are deduced for the 1p-1h state and for the compound states respectively. This seems to indicate that the isospin mixing widths are roughly independent of the complexity and lifetime of the state involved. (orig.)