Tau Polarimetry in B Meson Decays

Understand

This article summarizes recent developments in $B\to D^{(\ast)}\tau\nu$ decays.

• We explain how to extract the tau lepton's production properties from the kinematics of its decay products.
• The focus is on hadronic tau decays, which are most sensitive to the tau polarizations.
• We present new results for effects of new physics in tau polarization observables and quantify the observation prospects at BELLE II.