Charged-Higgs-boson effects in the B→Dτντ differential decay distribution

We show that the decay mode B -> D tau nu(tau) is competitive with and complementary to B -> tau nu(tau) in the search for charged-Higgs effects. Updating the relevant form factors, we find that the differential distribution in the decay chain (B) over bar -> D (nu) over bar (tau)tau(-)[-> pi(-) nu(tau)] excellently discriminates between standard model and charged-Higgs contributions. By measuring the D and pi(-) energies and the angle between the D and pi(-) three-momenta, one can determine the effective charged-Higgs coupling including a possible CP-violating phase.