D tau nu differential decay distribution > We present a detailed analysis of charged-Higgs effects in the decay B → D
tau nu. Updating the relevant formfactors, we find this decay mode competitive
with and complementary to B → tau nu. The differential distribution in the
decay chain B → D nu tau[→ pi nu] excellently discriminates between
Standard-Model and charged-Higgs contributions. By measuring the D and pi
energies and the angle between the D and pi tracks one can determine the
magnitude and phase of the effective charged-Higgs coupling g_S.