Measurement of the $D^{\ast }$ longitudinal polarization in $B^0\to D^{\ast -}{\tau }^{+}{\nu }_{\tau }$ decays

LHCb collaboration, R. Aaij, A. S. W. Abdelmotteleb +1091

The longitudinal polarization fraction of the $D^{\ast }$ meson is measured in $B^0\to D^{\ast -}{\tau }^{+}{\nu }_{\tau }$ decays, where the $\tau$ lepton decays to three charged pions and a neutrino, using…