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High Precision Measurement of the Superallowed 0^+ to 0^+ Beta Decay of ^{22}Mg

J. C. Hardy·V. E. Iacob·M. Sanchez-Vega·R. G. Neilson·A. Azhari·C. A. Gagliardi·V. E. Mayes·X. Tang·L. Trache·R. E. Tribble
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Abstract

The half-life, 3.8755(12) s, and superallowed branching ratio, 0.5315(12), for ^{22}Mg beta-decay have been measured with high precision. The latter depended on gamma-ray intensities being measured with an HPGe detector calibrated for relative efficiencies to an unprecedented 0.15%. Previous precise measurements of 0^+ to 0^+ transitions have been restricted to the nine that populate stable daughter nuclei. No more such cases exist, and any improvement in a critical CKM unitarity test must depend on precise measurements of more exotic nuclei. With this branching-ratio measurement, we show those to be possible for T_z = -1 parents. We obtain a corrected Ft-value of 3071(9) s, in good agreement with expectations.

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J. C. Hardy, V. E. Iacob, M. Sanchez-Vega, R. G. Neilson, A. Azhari, C. A. Gagliardi, V. E. Mayes, X. Tang, L. Trache, R. E. Tribble. 2003-07-31. High Precision Measurement of the Superallowed 0^+ to 0^+ Beta Decay of ^{22}Mg. https://doi.org/10.1103/physrevlett.91.082501

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