Prospects of searches for $b\to s\nu\bar{\nu}$ decays at FCC-ee

We investigate the physics reach and potential for the study of various decays based on the $b\to s\neu\neub$ transition at the Future Circular Collider running electron-positron collisions at the $Z$-pole (FCC-ee).

Signal and background candidates, which involve inclusive $Z$ contributions from $b\bar{b}$, $c\bar{c}$ and $uds$ final states, are simulated for a proposed multi-purpose detector. Signal candidates are selected using two Boosted Decision Tree algorithms.

We determine expected sensitivities at $\mathcal{O}(1\%)$ for the $B^0 \to K^{*0} \nu \bar{nu}$, $Bs^0 \to \phi \nu \bar{nu}$, $B^0 \to K{S}^{0} \nu \bar{nu}$ and  $\Lambda_b^0 \to \Lambda^{0} \nu \bar{nu}$ decays and investigate the impact of detector design choices related to particle-identification and vertex resolution.

The phenomenological impact of such measurements on various New Physics scenarios is also studied.