Stefan Wallner

18 February 2024
Lake Louise Winter Institute 2024

Abstract: Belle and its successor, the Belle II experiment at the KEK accelerator facility in Japan, measured large data sets of tau pair production. By applying innovative analysis techniques, we have obtained world-leading results from these data for precision measurements of the tau and Standard Model parameters, and for the search for physics beyond the Standard Model. In addition, special triggers designed to record events with low track multiplicity allow us to perform dart sector searches with unprecedented precision. In this talk we will report on the precision measurement of the tau mass and the partial wave decomposition in $\tau^-\to\pi^-\pi^-\pi^+\nu_\tau$ decays, the search for lepton flavor violation in tau decays, and the search for a dark $Z` in different final states.