Abstract
We address the nonperturbative calculation of the inclusive decay rate of semileptonic B(s)-meson decays from lattice QCD. Precise Standard-Model predictions are key ingredients in searches for new physics, and this type of computation may eventually provide new insight into the long-standing tension between the inclusive and exclusive determinations of the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements |Vcb| and |Vub|. We present results from a pilot lattice computation for Bs → Xc lνl, where the initial b quark described by the relativistic-heavy-quark (RHQ) formalism on the lattice and the other valence quarks discretised with domain-wall fermions are simulated approximately at their physical quark masses. We compare two different methods for computing the decay rate from lattice data of Euclidean n-point functions, namely Chebyshev and Backus-Gilbert approaches. We further study how much the ground-state meson dominates the inclusive decay rate and indicate our strategy towards a computation with a more comprehensive systematic error budget.
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Acknowledgments
This work used the DiRAC Extreme Scaling service at the University of Edinburgh, operated by the Edinburgh Parallel Computing Centre on behalf of the STFC DiRAC HPC Facility (www.dirac.ac.uk). This equipment was funded by BEIS capital funding via STFC capital grant ST/R00238X/1 and STFC DiRAC Operations grant ST/R001006/1. DiRAC is part of the National e-Infrastructure. A.B. is a JSPS International Research Fellows and received funding from the “JSPS Postdoctoral Fellowship for Research in Japan (Short-term)” and is supported by the Mayflower scholarship in the School of Physics and Astronomy of the University of Southampton. The work of S.H. and T.K. is supported in part by JSPS KAKENHI Grant Number 22H00138 and 21H01085 respectively and by the Post-K and Fugaku supercomputer project through the Joint Institute for Computational Fundamental Science (JICFuS).
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Barone, A., Hashimoto, S., Jüttner, A. et al. Approaches to inclusive semileptonic B(s)-meson decays from Lattice QCD. J. High Energ. Phys. 2023, 145 (2023). https://doi.org/10.1007/JHEP07(2023)145
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DOI: https://doi.org/10.1007/JHEP07(2023)145