For three-body decay of a nuclear level, it is suggested that instead of the total width being the sum of the partial widths calculated from $R$-matrix formulas the contributions from different decay channels should be added coherently. Two-proton and two-neutron decay widths are considered, and also widths of levels of ${}^9\mathrm{Be}$ and ${}^9\mathrm{B}$.

• Received 26 June 2003

DOI:https://doi.org/10.1103/PhysRevC.68.054602