Standard Model predictions for lepton flavour universality ratios of inclusive semileptonic B decays

Abstract

Abstract We present Standard Model predictions for lepton flavour universality ratios of inclusive B → X(c) ℓ ν ¯ ℓ $$ \ell {\overline{\nu}}_{\ell } $$ . For the ℓ = μ, e, these ratios are very close to unity as expected. For the τ mode, we update the SM prediction for the branching ratio including power-corrections in the heavy-quark expansion up to 1/ m b 3 $$ {m}_b^3 $$ . These inclusive ratios serve as an important cross-check of the exclusive B → D (*) ℓ ν ¯ ℓ $$ \ell {\overline{\nu}}_{\ell } $$ modes, in which tensions exists between the predictions and measurements in those modes.

Keywords

• Bottom Quarks
• Semi-Leptonic Decays