RK(⁎)ν and non-standard neutrino interactions

We discuss the modes B→K(⁎)νν¯ in the context of non-standard neutrino interactions that add incoherently to the SM rates. We consider two scenarios: an additional light neutrino; and neutrino lepton flavour violation. We find that an additional light neutrino that interacts with SM fields via a non-universal Z′ can increase RK(⁎)ν by up to a factor of two without conflicting with Bs−B¯s mixing. This model then predicts rates for Bs→τ+τ− up to six times larger than the SM. In the context of neutrino lepton flavour violation mediated by leptoquarks we find that the current experimental upper bounds on RK(⁎)ν are already more constraining than direct bounds from Bs→τℓ and B→K(⁎)τℓ modes for ℓ=e,μ.