$Q_{ extrm{EC}}$-value determination for $^{21}$Na$<br />ightarrow^{21}$Ne and $^{23}$Mg$<br />ightarrow^{23}$Na mirror-nuclei decays using high-precision mass spectrometry with ISOLTRAP at ISOLDE/CERN

We report on high-precision $Q_{ extrm{EC}}$ values of the $^{21}$Na$
ightarrow^{21}$Ne and $^{23}$Mg$
ightarrow^{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 $Q_{ extrm{EC}}$ 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$
ightarrow^{21}$Ne $Q_{ extrm{EC}}$ value, a $2.3 sigma$ deviation from the literature $Q_{ extrm{EC}}$-value was found.

Karthein, J., Atanasov, D., Blaum, K., Breitenfeldt, M., Bondar, V., George, S., ... Zuber, K.

Karthein, Jonas||Atanasov, Dinko||Blaum, Klaus||Breitenfeldt, Martin||Bondar, Vira||George, Sebastian||Hayen, Leendert||Lunney, David||Manea, Vladimir||Mougeot, Maxime||Neidherr, Dennis||Schweikhard, Lutz||Severijns, Nathal||Welker, Andree||Wienholtz, Frank||Wolf, Robert||Zuber, Kai

$Q_{ extrm{EC}}$-value determination for $^{21}$Na$
ightarrow^{21}$Ne and $^{23}$Mg$
ightarrow^{23}$Na mirror-nuclei decays using high-precision mass spectrometry with ISOLTRAP at ISOLDE/CERN Institutional Repository Document