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Measurement of the Forward-Backward Asymmetries of e+e- -> Z -> b bbar and e+e- -> Z -> c cbar using prompt leptons

The DELPHI Collaboration·J. Abdallah
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Abstract

The forward-backward asymmetries of the processes e+e- -> Z -> b bbar and e+e- -> Z -> c cbar were measured from a sample of hadronic Z decays collected by the DELPHI experiment between 1993 and 1995. Enriched samples of b bbar and c cbar events were obtained using lifetime information. The tagging of b and c quarks in these samples was based on the semileptonic decay channels b/c -> X + mu and b/c -> X + e combined with charge flow information from the hemisphere opposite to the lepton. Combining the A_{FB}^{b bbar} and A_{FB}^{c cbar} measurements presented in this paper with published results based on 1991 and 1992 DELPHI data samples, the following pole asymmetries were obtained: A_{FB}^{0,b} = 0.1021 +/- 0.0052 (stat) +/- 0.0024 (syst) A_{FB}^{0,c} = 0.0728 +/- 0.0086 (stat) +/- 0.0063 (syst) The effective value of the weak mixing angle derived from these measurements is sin^2 theta_{W,eff}^{lept} = 0.23170 +/- 0.00097 .

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The DELPHI Collaboration, J. Abdallah. 2004-03-27. Measurement of the Forward-Backward Asymmetries of e+e- -> Z -> b bbar and e+e- -> Z -> c cbar using prompt leptons. https://doi.org/10.1140/epjc%2Fs2004-01708-6

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