Measurements of \(R_{\rm b}\), \(A_{\rm FB}^{\rm b}\), and \(A_{\rm FB}^{\rm c}\) in \({\rm e^+ e^-}\) collisions at 130 – 189 GeV

  • The OPAL Collaboration
  • G. Abbiendi et al.
Experimental physics


The cross-section ratio \(R_{\mathrm{b}} = \sigma( \rm e^+ e^- \to{\rm b\overline{\rm b}} )/\sigma(\rm e^+ e^-\to{\mathrm q\bar{\mathrm q}} )\) and the bottom and charm forward-backward asymmetries \(A_{\mathrm{FB}}^{\mathrm{b}}\) and \(A_{\mathrm{FB}}^{\mathrm c}\) are measured using event samples collected by the OPAL detector at centre-of-mass energies between 130 and 189 GeV. Events with bottom quark production are selected with a secondary vertex tag, and a hemisphere charge algorithm is used to extract \(A_{\mathrm{FB}}^{\mathrm{b}}\). In addition, the bottom and charm asymmetries are measured using leptons from semileptonic decays of heavy hadrons and pions from \(\mathrm{D}^{*+}\to\rm D^0{\pi^+}\) decays. The results are in agreement with the Standard Model predictions.


Model Prediction Opal Detector Event Sample Standard Model Prediction Bottom Quark 
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Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • The OPAL Collaboration
  • G. Abbiendi et al.
    • 1
  1. 1.Dipartimento di Fisica dell' Università di Bologna and INFN, 40126 Bologna, Italy IT

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