We report the first direct measurement of the $^{ 14}\text{ O}$ superallowed Fermi $\beta$-decay $Q_{ EC}$-value, the last of the so-called "traditional nine" superallowed Fermi $\beta$-decays to be measured with Penning trap mass spectrometry. $^{ 14}$O, along with the other low-$Z$ superallowed $\beta$-emitter, $^{ 10}$C, is crucial for setting limits on the existence of possible scalar currents. The new ground state $Q_{ EC}$ value, 5144.364(25) keV, when combined with the energy of the $0^+$ daughter state, $E_x(0^+)=2312.798(11)$~keV [Nucl. Phys. A { \bf{ 523}}, 1 (1991)], provides a new determination of the superallowed $\beta$-decay $Q_{ EC}$ value, $Q_{ EC}(\text{ sa}) = 2831.566(28)$ keV, with an order of magnitude improvement in precision, and a similar improvement to the calculated statistical rate function $f$. This is used to calculate an improved $\mathcal{ F}t$-value of 3073.8(2.8) s.
Categories: nucl-ex