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arXiv · 2309.16893

Data-driven reevaluation of $ft$-values in superallowed $\beta$ decays

Chien-Yeah Seng·Mikhail Gorchtein
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Abstract

We present a comprehensive re-evaluation of the $ft$ values in superallowed nuclear $\beta$ decays crucial for the precise determination of $V_{ud}$ and low-energy tests of the electroweak Standard Model. It consists of the first, fully data-driven analysis of the nuclear $\beta$ decay form factor, that utilizes isospin relations to connect the nuclear charged weak distribution to the measurable charge distributions. This prescription supersedes previous shell-model estimations, and allows for a rigorous quantification of theory uncertainties in $f$ which is absent in the existing literature. Our new evaluation shows an overall downward shift of the central values of $f$ at the level of 0.01\%.

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Chien-Yeah Seng, Mikhail Gorchtein. 2023-09-28. Data-driven reevaluation of $ft$-values in superallowed $\beta$ decays. https://doi.org/10.1103/physrevc.109.045501

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