τ polarization asymmetry in B→X_sτ₊τ-

Rare B decays provide an opportunity to probe for new physics beyond the standard model. In this paper, we propose to measure the τ polarization in the inclusive decay B→X_sτ₊τ- and discuss how it can be used, in conjunction with other observables, to completely determine the parameters of the flavor-changing low-energy effective Hamiltonian. Both the standard model and several new physics scenarios are examined. This process has a large enough branching fraction, few×10^-7, such that sufficient statistics will eventually be provided by the B factories currently under construction.