$Q_{\text{EC}}$-value determination for ${}^{21}$Na${\to }^{21}$Ne and ${}^{23}$Mg${\to }^{23}$Na mirror-nuclei decays using high-precision mass spectrometry with ISOLTRAP at ISOLDE/CERN

Abstract

We report on high-precision $Q_{\text{EC}}$ values of the ${}^{21}$Na${\to }^{21}$Ne and ${}^{23}$Mg${\to }^{23}$Na mirror $\beta$-transitions from mass measurements with ISOLTRAP at ISOLDE/CERN. A precision of $\delta m/m=9\cdot 10^{-10}$ and $\delta m/m=1.5\cdot 10^{-9}$ was reached for the masses of ${}^{21}$Na and ${}^{23}$Mg, respectively. We reduce the uncertainty of the $Q_{\text{EC}}$ values by a factor five, making them the most precise experimental input data for the calculation of the corrected $\mathcal{F}t$-value of these mixed Fermi/Gamow-Teller transitions. For the ${}^{21}$Na${\to }^{21}$Ne $Q_{\text{EC}}$ value, a $2.3\sigma$ deviation from the literature $Q_{\text{EC}}$-value was found.

Published by Physical Review C. 8 pages, 6 figures, 2 tables