26-30 July 2021
Europe/Berlin timezone

A new determination of $|V_{cb}|$ using inclusive $q^2$ moments of $B \to X_c \ell \bar \nu_\ell$ decays

27 Jul 2021, 11:00


Parallel session talk Flavour Physics and CP Violation T08: Flavour Physics and CP Violation


Kevin Olschewsky


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.

Email olschewsky@physik.uni-siegen.de
First author Kevin Olschewsky
Collaboration / Activity Collaborative Research

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