Pushing the Heavy Quark Expansion for b ? cl(Equation presented) to Higher Order in 1/m<inf>b</inf>

The Heavy Quark Expansion (HQE) is the major tool to perform calculations for inclusive semileptonic B ? Xcl(Equation presented) and, consequently, for precision determinations of the CKM matrix element Vcb. To further improve precision, we pushed the expansion to 1/m5b to include even higher order terms in the HQE. Notably, at 1/m5b, “intrinsic charm” (IC) contributions proportional to 1/(m3bm2c) occur, which are numerically expected to be sizeable. We will therefore firstly discuss the determination of a reduced set of HQE parameters at 1/m5b, employing Reparametrisation Invariance (RPI) to this end. Consequently, we will show how the IC and “genuine" 1/m5b contribute to the different kinematical moments of B ? Xcl(Equation presented), focusing in this work on the lepton energy El moments. Using the “lowest-lying state saturation ansatz” (LLSA), we estimate the size of these contributions and observe a partial cancellation between the IC and “genuine” 1/m5b contributions, leading to an overall small contribution.