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Measurements of BR (b ---> tau- anti-nu(tau) X) and BR (b ---> tau- anti-nu(tau) D*+- X) and upper limits on BR (B- ---> tau- anti-nu(tau)) and BR (b---> s nu anti-nu)

Research output: Contribution to journalJournal article


<mark>Journal publication date</mark>02/2001
<mark>Journal</mark>European Physical Journal C: Particles and Fields
Issue number2
Number of pages15
Pages (from-to)213-227
<mark>Original language</mark>English


Inclusive branching ratios involving b →τ transitions are measured in approximately four million hadronic Z decays collected by the ALEPH detector at LEP. The fully-inclusive branching ratio BR(b →τ−ν¯τ X) and the semi-inclusive branching ratio BR(b →τ−ν¯τD∗± 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 −→τ−ν¯τ) and BR(b →sνν¯) are set to 8.3×10−4 and 6.4×10−4 at the 90% C.L. These results allow a 90% C.L. lower limit of 0.40 GeV/ c2)−1 to be set on the tanβ/mH± ratio, in the framework of type-II two-Higgs-doublet models.