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

Abstract

Abstract We investigate the physics reach and potential for the study of various decays involving a $$ b\to s\nu \overline{\nu} $$ b → sν ν ¯ 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 $$ b\overline{b} $$ b b ¯ , $$ c\overline{c} $$ c 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 relative sensitivities of 0.53%, 1.20%, 3.37% and 9.86% for the branching fractions of the $$ {B}^0\to {K}^{\ast 0}\nu \overline{\nu} $$ B 0 → K ∗ 0 ν ν ¯ , $$ {B}_s^0\to \phi \nu \overline{\nu} $$ B s 0 → ϕν ν ¯ , $$ {B}^0\to {K}_S^0\nu \overline{\nu} $$ B 0 → K S 0 ν ν ¯ and $$ {\Lambda}_b^0\to \Lambda \nu \overline{\nu} $$ Λ b 0 → Λ ν ν ¯ decays, respectively. In addition, we investigate the impact of detector design choices related to particle-identification and vertex resolution. The phenomenological impact of such measurements on the extraction of Standard Model and new physics parameters is also studied.