Geraldine Raeuber

29 June 2023
FPCP2023

Abstract: Belle has unique sensitivity to a broad class of models that postulate the existence of dark matter particles with MeV—GeV masses. In addition, the low-background environment of electron-positron collisions along with the large expected sample size and an hermetic detector make Belle II the premier experiment for studying tau-lepton physics. This talk presents recent world-leading physics results from Belle II searches for dark Z’ decays; as well as for long-lived (pseudo) scalars in B decays. Results from Belle II determinations of the tau lepton mass and from searches lepton-flavor-violating τ decays to a lepton and an invisible boson are presented.