Polarization in semileptonic \mathrm{B}\rightarrow X\tau decays

The paper gives the polarization of the tau lepton in the semileptonic B decays with respect to the direction of the virtual W boson. The result given includes the nonperturbative HQET corrections. The perturbative QCD corrections are probably negligible, as is suggested by the existing results for the longitudinal polarization of the charged lepton (Jeżabek and Urban, 1998). Received: 14 January 1999 / Revised version: 14 May 1999 / Published online: 14 October 1999