Measurement of the fraction of hadronic Z decays into charm quark pairs

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


The full statistics of hadronic Z decays collected with the ALEPH detector are analysed to measure, by three methods, the ratio, \({\rm R_c}\), of the partial decay width of the Z into \({\rm c\bar c}\) quarks to the total hadronic width. One method uses the inclusive \(p\) and \(p_{\perp}\) spectra of electrons. The other two use a double-tagging technique to measure \({\rm R_c}\) independently of the charm-tagging efficiency. In one, the tagging procedure uses the reconstruction of high momentum charmed mesons (\({\rm D^{*+}}\), \({\rm D^+}\) and \({\rm D^0}\) to detect the charm quarks. In the other, a charm quark is tagged from the \({\rm D^*}\)'s reconstructed in the \({\rm D^{*+} \to \pi^+ D^0}\) decay channel and the other from the slow pion from the \({\rm D^{*-} \to \pi^- \bar{D}^0}\) decay. The combination of these measurements leads to \({\rm R_c = \Gamma(Z \to c\bar c) / \Gamma(Z \to hadrons)}) = 0.1681\pm0.0054({\rm stat})\pm0.0062({\rm syst})\).


Decay Width Decay Channel High Momentum Charm Quark Full Statistic 
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 1998

Authors and Affiliations

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

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