Speaker
Description
The Heavy Quark Expansion (HQE) has become the major tool to perform precision calculations for inclusive heavy hadron decays. With this method, $V_{cb}$ has been extracted with percent-level precision from moments of $B\to X_c\ell\bar{\nu}$. The HQE is an expansion in $1/m_b$ and introduces nonperturbative HQE matrix elements which can be extracted from data.
To further increase the theoretical precision, we recently pushed the expansion to $1/m_b^5$. We focused on reparametrization invariant (RPI) observables, which depend on a reduced set of HQE parameters. Specifically, at $1/m_b^5$, "intrinsic charm" (IC) contributions proportional to $1/(m_b^3m_c^3)$ enter, which are numerically expected to be sizeable.
I will show how the $1/m_b^5$ contribute to the $q^2$ moments of $B\to X_c\ell\bar{\nu}$ decays. We found that the total $1/m_b^5$ contributions may not be as sizeable as expected. I will discuss how this may impact a future inclusive $V_{cb}$ determination.
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