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

Abstract

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 → 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.

Keywords

• Bottom Quarks
• Hadronic Matrix Elements and Weak Decays
• Lattice QCD
• Semi-Leptonic Decays