Disentangling $V_{ud}$ from New Physics in Beta Decays with the FCC-ee

Lemonia Gialidi, Elie Hammou, Kamil Laurent +3

Superallowed nuclear $\beta$-decays enable the most precise determination of the CKM element $V_{ud}$, but they are only sensitive to an effective combination of $V_{ud}$ and New Physi…