An exclusive coincidence experiment using the (p, nIASp˜) reaction on 140Ce, 172,174,176Yb, and 208Pb was carried out for the first time by measuring decay protons from the isobaric analog states (IAS). Spreading widths of the IAS are deduced from the escape and total widths. The results show a strong isospin dependence which can be explained by the isospin mixing effect due to the coupling to the T0 component among three multiplets T = T0 − 1, T0, and T0 + 1 of isovector monopole states in daughter nuclei. Empirical isospin mixing probabilities are found to be consistent with microscopic sum rule predictions.
ASJC Scopus subject areas
- Physics and Astronomy(all)