Speaker
Description
Precision determination of the CKM matrix element $|V_{cb}|$ are important to test the unitarity of the CKM matrix and to search for loop-level new physics effects. In this talk, we present a new determination of $|V_{cb}|$ using measured $q^2$ moments from $B \to X_c \ell \bar \nu_\ell$ decays provided by the Belle and Belle II collaborations. This new experimental input is the key ingredient to determine the non-perturbative hadronic matrix elements entering the total semileptonic $B \to X_c \ell \bar \nu_\ell$ rate in the heavy-quark expansion. Exploiting reparametrization invariance, the number of these non-perturbative parameters can be reduced to 8 at $\mathcal{O}(1/m_b^4)$. The value of these parameters and $|V_{cb}|$ is simultaneously determined, taking into account also the theoretical uncertainties from missing higher order contributions in the heavy quark expansion and corrections from the strong interaction.
| First author | Kevin Olschewsky |
|---|---|
| olschewsky@physik.uni-siegen.de | |
| Collaboration / Activity | Collaborative Research |
