First $\beta$- and $\gamma$-spectroscopic decay studies of the $N=82$ $r$-process “waiting-point” nuclide ${}^{130}\mathrm{C}\mathrm{d}$ have been performed at CERN/ISOLDE using the highest achievable isotopic selectivity. Several nuclear-physics surprises have been discovered. The first one is the unanticipatedly high energy of 2.12 MeV for the [$\pi g_{9/2}\otimes \nu g_{7/2}]$ $1^{+}$ level in ${}^{130}\mathrm{I}\mathrm{n}$, which is fed by the main Gamow-Teller transition. The second surprise is the rather high $Q_{\beta }$ value of 8.34 MeV, which is in agreement only with recent mass models that include the phenomenon of $N=82$ shell quenching. Possible implications of these new results on the formation of the $A\simeq 130$ $r$-process abundance peak are presented.

• Received 28 July 2003

DOI:https://doi.org/10.1103/PhysRevLett.91.162503