Beta delayed proton decay of the proton dripline nucleus Ho-142

Unknown \ensuremath{\beta}-delayed proton precursor ${}^{142}\mathrm{Ho}$ was synthesized in the reaction ${}^{106}\mathrm{Cd}$ ${(}^{40}\mathrm{Ca},p3n)$ and identified for the first time using proton-gamma coincidence measurements in combination with a helium-jet fast tape-transport system. Its \ensuremath{\beta}-delayed proton spectrum was observed. The half-life of ${}^{142}\mathrm{Ho}$ was determined to be $0.4\ifmmode\pm\else\textpm\fi{}0.1 \mathrm{s}.$ According to the estimated relative branching ratios to the final states in the daughter nucleus, the ground-state spin of ${}^{142}\mathrm{Ho}$ could be assigned as 6, 7, or 8.