Inclusive B ¯ → X s ℓ + ℓ − $$ \overline{B}\to {X}_s{\ell}^{+}{\ell}^{-} $$ at the LHC: theory predictions and new-physics reach

Abstract

Abstract We present theoretical predictions for observables in inclusive B ¯ → X s ℓ + ℓ − $$ \overline{B}\to {X}_s{\ell}^{+}{\ell}^{-} $$ suitable for measurements at hadron colliders through a sum-over-exclusive approach. At low q 2 we calculate the branching ratio and three angular observables. At high q 2 we provide the branching ratio and the ratio of the B ¯ → X s ℓ + ℓ − $$ \overline{B}\to {X}_s{\ell}^{+}{\ell}^{-} $$ rate with respect to the inclusive B ¯ → X u ℓ ν ¯ $$ \overline{B}\to {X}_u\ell \overline{\nu} $$ rate with the same phase-space cut. We compare our predictions to the B factory measurements and also to an extraction of the experimental rate through a sum-over-exclusive method using branching ratios of the exclusive B ¯ → K ∗ μ + μ − $$ \overline{B}\to {K}^{\left(\ast \right)}{\mu}^{+}{\mu}^{-} $$ modes measured at LHCb. We find a consistent picture comparing Standard Model theory and experiment. As such, our analysis does not support a recent claim about a deficit in the inclusive branching ratio in the high-q 2 region. Finally, we present current model-independent bounds on new physics and emphasize the potential of complementary analyses of B ¯ → X s ℓ + ℓ − $$ \overline{B}\to {X}_s{\ell}^{+}{\ell}^{-} $$ at Belle II and the LHC.

Keywords

• Bottom Quarks
• Rare Decays
• Semi-Leptonic Decays