B → K ∗ ν ν ¯ $$ B\to {K}^{\left(\ast \right)}\nu \overline{\nu} $$ decays in the Standard Model and beyond

Abstract

We present an analysis of the rare exclusive B decays $$ B\to K\nu \overline{\nu} $$ and $$ B\to {K}^{\ast}\nu \overline{\nu} $$ within the Standard Model (SM), in a model-independent manner, and in a number of new physics (NP) models. Combining new form factor determinations from lattice QCD with light-cone sum rule results and including complete two-loop electroweak corrections to the SM Wilson coefficient, we obtain the SM predictions $$ \mathrm{B}\mathrm{R}\left({B}^{+}\to {K}^{+}\nu \overline{\nu}\right)=\left(4.0\pm 0.5\right)\times 1{0}^{-6} $$ and $$ \mathrm{B}\mathrm{R}\left({B}^0\to {K}^{\ast 0}\nu \overline{\nu}\right)=\left(9.2\pm 1.0\right)\times 1{0}^{-6} $$ , more precise and more robust than previous estimates. Beyond the SM, we make use of an effective theory with dimension-six operators invariant under the SM gauge symmetries to relate NP effects in $$ b\to s\nu \overline{\nu} $$ transitions to b → sℓ + ℓ − transitions and use the wealth of experimental data on B → K (∗) ℓ + ℓ − and related modes to constrain NP effects in $$ B\to {K}^{\left(\ast \right)}\nu \overline{\nu} $$ . We then consider several specific NP models, including Z′ models, the MSSM, models with partial compositeness, and leptoquark models, demonstrating that the correlations between $$ b\to s\nu \overline{\nu} $$ observables among themselves and with B s → μ + μ − and b → sℓ + ℓ − transitions offer powerful tests of NP with new right-handed couplings and non-MFV interactions.