Studies of B→τν and B→D(⁎)τν decays at BaBar

Decays of B mesons into final states containing a τ lepton are sensitive to new-physics contributions involving charged Higgs bosons or other charged-current interactions that violate lepton universality. The BaBar experiment has reported evidence for the decay B→τν and observed significant signals for the decays B→D⁎τν and B→Dτν. The agreement of these results with the Standard-Model expectation is evaluated, and tight constraints are placed on type-II two-Higgs-doublet-model scenarios.