Data-driven reevaluation of $ft$-values in superallowed $\beta$ decays
- Resource Type
- Working Paper
- Authors
- Seng, Chien-Yeah; Gorchtein, Mikhail
- Source
- Phys.Rev.C 109, 045501 (2024)
- Subject
- Nuclear Theory
High Energy Physics - Experiment
High Energy Physics - Phenomenology
Nuclear Experiment
- Language
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\%.
Comment: Version accepted by PRC