$\beta$-Decay Half-Life of the $rp$-Process Waiting Point Nuclide ${}^{84}$Mo

A half-life of 2.2 $\pm$ 0.2 s has been deduced for the ground-state $\beta$ decay of ${}^{84}$Mo, more than 1$\sigma$ shorter than the previously adopted value. ${}^{84}$Mo is an even-even N = Z nucleus lying on the proton dripline, created during explosive hydrogen burning in Type I X-ray bursts in the rapid proton capture ($rp$) process. The effect of the measured half-life on $rp$-process reaction flow is explored. Implications on theoretical treatments of nuclear deformation in ${}^{84}$Mo are also discussed.