Revisiting $$B\rightarrow K^{(*)} \nu {\bar{\nu }}$$ decays in the Standard Model and beyond

Abstract In this letter we revisit the Standard Model predictions for $${\mathcal {B}}(B\rightarrow K^{(*)}\nu {\bar{\nu }})$$ B ( → K ∗ ) ν ¯ and discuss opportunities that open up when combining its partial decay rate with of $$B\rightarrow K^{(*)}\ell \ell $$ ℓ . a suitable ratio these two modes can be used to extract $$C_9^\textrm{eff}$$ C 9 eff , which is essential reliable phenomenological analysis angular observables. The same also proves more sensitive presence New Physics in many plausible extensions Model. We suggest separate measurement K\nu high low $$q^2$$ q 2 ’s helpful testing assumed shape vector form factor, because lattice QCD data are obtained at ’s, whereas region through an extrapolation.