Precision half-life measurement of the \boldmath${\beta }^{+}$ decay of \tsups{37}K

Abstract

The half-life of \tsups{37}K has been measured to be $1.23651(94)\mathrm{s}$, a value nearly an order of magnitude more precise than the best previously reported. The ${\beta }^{+}$ decay of \tsups{37}K occurs mainly via a superallowed branch to the ground-state of its $T=1/2$ mirror, \tsups{37}Ar. This transition has been used recently, together with similar transitions from four other nuclei, as an alternative test of CVC and method for determining $V_{ud}$, but the precision of its $ft$ value was limited by the relatively large half-life uncertainty. Our result corrects that situation. Another motivation for improving the $ft$ value was to determine the standard-model prediction for the $\beta$-decay correlation parameters, which will be compared to those currently being measured by the \trinat{} collaboration at \triumf. The new $ft$ value, $4605(8)\mathrm{s}$, is now limited in precision by the $97.99(14)\%$ ground-state branching ratio.

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Cited by in corpus (10)

• Comprehensive analysis of beta decays within and beyond the Standard Model
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• Symmetry violations in nuclear and neutron $\beta$ decay
• Precision measurement of the $\beta$-asymmetry in spin-polarized ${}^{37}\mathrm{K}$ decay
• $\mathcal{F}t$ values of the mirror $\beta$ transitions and the weak magnetism induced current in allowed nuclear $\beta$ decay
• All orders factorization and the Coulomb problem
• Field Theory of the Fermi Function
• Constraints on subleading interactions in beta decay Lagrangian
• High Precision Measurement of the ${}^{19}$Ne Half-life using real-time digital acquisition
• $A_{\beta }[E_{\beta }]$ in ${}^{37}$K decay: new physics with opposite $\beta$ helicity