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Measurements of BR(b \(\to \tau^- \bar{\nu}_{\tau}\)X) and BR(b\(\to \tau^- \bar{\nu}_{\tau}{\mathrm D}^{\ast\pm}\) X) and upper limits on BR(B\(^- \to \tau^- \bar{\nu}_{\tau})\) and BR(b \(\to{\mathrm s} \nu \bar{\nu})\)

  • The ALEPH Collaboration
  • R. Barate et al.
Experimental physics

Abstract.

Inclusive branching ratios involving b \(\to \tau\) transitions are measured in approximately four million hadronic Z decays collected by the ALEPH detector at LEP. The fully-inclusive branching ratio BR(b \(\to \tau^- \bar{\nu}_{\tau}\) X) and the semi-inclusive branching ratio BR(b \(\to \tau^- \bar{\nu}_{\tau} {\rm D}^{\ast\pm}\)X) are measured to be \((2.43 \pm 0.20 \pm 0.25)%\) and \((0.88\pm 0.31\pm 0.28)%\), in agreement with the standard model predictions. Upper limits on the branching fractions BR(B\(^- \to \tau^- \bar{\nu}_{\tau})\) and BR(b \(\to{\mathrm s} \nu \bar{\nu})\) are set to \(8.3 \times 10^{-4}\) and \(6.4 \times 10^{-4}\) 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 \(\tan\beta/m_{{\mathrm H}^\pm}\) ratio, in the framework of type-II two-Higgs-doublet models.

Keywords

Model Prediction Lower Limit Standard Model Prediction Aleph Detector 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2001

Authors and Affiliations

  • The ALEPH Collaboration
  • R. Barate et al.
    • 1
  1. 1.Laboratoire de Physique des Particules (LAPP), IN2P3-CNRS, 74019 Annecy-le-Vieux Cedex, France FR

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