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Article
Report number	arXiv:2305.14092 ; KEK-CP-0394 ; CERN-TH-2023-087
Title	Approaches to inclusive semileptonic B$_{(s)}$-meson decays from Lattice QCD
Author(s)	Barone, Alessandro (Southampton U. ; KEK, Tsukuba) ; Hashimoto, Shoji (KEK, Tsukuba ; Sokendai, Tsukuba) ; Jüttner, Andreas (Southampton U. ; CERN) ; Kaneko, Takashi (KEK, Tsukuba ; Sokendai, Tsukuba ; KMI, Nagoya) ; Kellermann, Ryan (KEK, Tsukuba ; Sokendai, Tsukuba)
Publication	2023-07-18
Imprint	2023-05-23
Number of pages	43
In:	JHEP 2307 (2023) 145
DOI	10.1007/JHEP07(2023)145
Subject category	hep-ph ; Particle Physics - Phenomenology ; hep-lat ; Particle Physics - Lattice
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 $|V_{cb}|$ and $|V_{ub}|$. We present results from a pilot lattice computation for $B_s \rightarrow X_c\, l \nu_l$, 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.
Copyright/License	preprint: (License: arXiv nonexclusive-distrib 1.0) publication: © 2023-2025 The Authors (License: CC-BY-4.0), sponsored by SCOAP³

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