ENHANCED CHARGED-HIGGS-BOSON EFFECTS IN B--]TAU(NU)OVER-BAR, MU(NU)OVER-BAR AND B-]TAU(NU)OVER-BAR PLUS X

Charged Higgs boson effects are not helicity suppressed in the decays B- --> taunuBAR, munuBAR, and enuBAR, and could enhance or suppress these modes without violating lepton universality. The present limit of B(B- --> munuBAR) < 2.0 X 10(-5) is more stringent than the measurement B(b --> taunuBAR + X) = (4.20(+0.72/-0.68) +/- 0.46)%, while a factor of 2 improvement in the present limit of B (B- --> taunuBAR) < 1. 2% would be comparable. There is much room for discovery as one pushes the latter limit down to the standard model expectation of order 10(-4). A value below this may be explained without requiring f(B)\V(ub)\ to be unduly small.