Transverse tau polarization in inclusive B → τ ν X decays

We calculate, in the framework of multi Higgs doublet models, the CP violating transverse tau polarization, Pτ, in inclusive semileptonic B meson decays. We find that Pτ diverges at O(1mb2) of the heavy quark expansion. We discuss the physical reasons for this divergence and show how to regularize it. We find large 1mb2 corrections that can suppress the CP asymmetry by as much as 30%. The maximal allowed asymmetry is ac ∼ 0.34. We discuss how the allowed range is expected to change in the future.