Speaker
Mr
Ilija Milutin
(University of Siegen)
Description
The Heavy Quark Expansion has become the major tool for precision calculations for inclusive heavy hadron decays. The HQE is an expansion in $1/m_b$. Recently, moments of the dilepton spectrum of inclusive $B\to X_c\ell\bar{\nu}$ were used to precisely extract the CKM matrix element $V_{cb}$. Usually, one assumes that the charm quark is heavy, leading to $\Lambda_{\rm{QCD}}^n/m_c^n$-contributions. A consistent power counting therefore needs to be set up. Numerically, we find that $m_c^2\sim m_b\Lambda_{\rm{QCD}}$. Therefore, $m_c^2$ should be counted as one power of $m_b$. Consequently, we need to include $1/m_b^3\cdot1/m_c^2$-contributions to complete the existing calculation at $\mathcal{O}(1/m_b^4)$, which we will present here.
Authors
Mr
Ilija Milutin
(University of Siegen)
Keri Vos
(University of Maastricht)
Thomas Mannel
(Siegen University)
