Measurements of BR(b→τ-(ν)over-barτX) and BR(b→τ-(ν)over-barτD*±X) and upper limits on BR(B-→τ-(ν)over-barτ) and BR(b→sν(ν)over-bar)

Inclusive branching ratios involving b --> T transitions are measured in approximately four million hadronic Z decays collected by the ALEPH detector at LEP. The fully-inclusive branching ratio BR(b --> T-(v) over bar (T) X) and the semi-inclusive branching ratio BR(b --> T-(v) over bar D-T*X+/-) are measured to be (2.43 +/- 0.20 +/- 0.25)% and (0.88 +/- 0.31 +/- 0.28)%, in agreement with the standard model predictions, Upper limits. on the branching fractions BR(B- --> T- (v) over bar (T)) and BR(b --> sv (v) over bar) are set to 8.3 x 10(-4) and 6.4 x 10(-4) at the 90% C.L. These results allow a 90% C.L. lower limit of 0.40 (GeV / c(2))(-1) to be set on the tan beta / m(H)+/- ratio, in the framework of type-II two-Higgs-doublet models.