First direct determination of the superallowed ${\hat{I}}^2$-decay $Q_{EC}$-value for ${}^{14}$O

Abstract

We report the first direct measurement of the ${}^{14}\text{O}$ superallowed Fermi ${\hat{I}}^2$-decay $Q_{EC}$-value, the last of the so-called "traditional nine" superallowed Fermi ${\hat{I}}^2$-decays to be measured with Penning trap mass spectrometry. ${}^{14}$O, along with the other low-$Z$ superallowed ${\hat{I}}^2$-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 ${\hat{I}}^2$-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.

5 pages, 5 figures