The Ericson fluctuations of the mirror decays ${}_{}{}^{15}{}_{}{}^{}\mathrm{O}$+${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ and ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$+${}_{}{}^7{}_{}{}^{}\mathrm{Be}$ of a ${}_{}{}^{22}{}_{}{}^{}\mathrm{Na}$ compound state near 53-MeV excitation energy are found to be correlated, providing evidence that isospin is a good quantum number at this high excitation energy.

• Received 13 January 1971

DOI:https://doi.org/10.1103/PhysRevLett.26.448