Speaker
Roberta Volpe
(Charles University Prague)
Description
The Belle and Belle II experiments have collected a 1.2 ab$^{-1}$ sample of $e^+e^- \to B\bar B$ collisions at a centre-of-mass energy corresponding to the $\Upsilon(4S)$ resonance. These data, with low particle multiplicity and constrained initial state kinematics, are an ideal environment to search for rare electroweak penguin $B$ decays and lepton-flavour-violating decays to final states with missing energy from neutrinos.
Results from $b\to s\nu \bar{\nu}$ processes and their interpretation are presented. In addition, we present searches for the processes . Finally, we present our searches for the lepton-flavour violating decays $B \to K^{(*)} \tau^{\pm} \ell^{\mp}$, where $\ell$ is an electron or muon.