$R^ u_{K^{(*)}}$ and non-standard neutrino interactions

We discuss the modes $Bto K^{(*)} ubar u$ 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 $Z^prime$ can increase $R^ u_{K^{(*)}}$ by up to a factor of two without conflicting with $B_s-bar B_s$ mixing. This model then predicts rates for $B_sto tau^+tau^-$ 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 $R^ u_{K^{(*)}}$ are already more constraining than direct bounds from $B_sto tau ell$ and $Bto K^{(*)}tau ell$ modes for $ell=e,mu$.