Lepton Polarization in the Decays B → X s μ + μ − and B → X s τ + τ −

The effective Hamiltonian for the decay b → s l + l − predicts a characteristic polarization for the final state lepton, which can serve as an important test of the underlying theory. The lepton polarization has, in addition to a longitudinal component P L , two orthogonal components P T and P N , lying in and perpendicular to the decay plane which are proportional to m l /m b , and therefore significant for the τ + τ − channel. The normal polarization component P N is a T-odd effect connected with the nonhermiticity of the effective Hamiltonian, arising mainly from c¯ c intermediate states. We calculate all three polarization components for the decay B → X s τ + τ − as a function of the lepton pair mass, and