Approaches to inclusive semileptonic B(s)-meson decays from Lattice QCD

• Published in: The journal of high energy physics Vol. 2023; no. 7; pp. 145 - 43
• Main Authors: Barone, Alessandro, Hashimoto, Shoji, Jüttner, Andreas, Kaneko, Takashi, Kellermann, Ryan
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 18.07.2023; Springer Nature B.V; SpringerOpen
• Subjects: Approximation; Bottom Quarks; Chebyshev approximation; Classical and Quantum Gravitation; Computation; Decay rate; Domain walls; Elementary Particles; Euclidean space; Fermions; Hadronic Matrix Elements and Weak Decays; High energy physics; Lattice QCD; Particle decay; Physics; Physics and Astronomy; Polynomials; Quantum chromodynamics; Quantum Field Theories; Quantum Field Theory; Quantum Physics; Quarks; Regular Article - Theoretical Physics; Relativity Theory; Semi-Leptonic Decays; String Theory; Systematic errors; Hadronic Matrix Elements and Weak Decays; Lattice QCD; Bottom Quarks; Semi-Leptonic Decays
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP07(2023)145

A bstract 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 → X c lν 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.