Polarization of tau leptons in semileptonic B decays Original Research Article

Analytic formulae for the as order QCD corrections to the differential width of the semileptonic b decay are given with the T polarization taken into account. Thence the polarization of τ is expressed by its energy and the invariant mass of the τ + v system. The non-perturbative corrections by Falk et al. are incorporated in the calculation.