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Measurement of the forward backward asymmetry of c and b quarks at the Z pole using reconstructed D mesons (2006)

Abstract
A measurement of the forward--backward asymmetry of $e^{+}e^{-} \to c\bar{c}$ and $e^{+}e^{-} \to b\bar{b}$ on the $Z$ resonance is performed using about 3.5 million hadronic $Z$ decays collected by the DELPHI detector at LEP in the years 1992 to 1995. The heavy quark is tagged by the exclusive reconstruction of several $D$ meson decay modes. The forward--backward asymmetries for $c$ and $b$ quarks at the $Z$ resonance are determined to be: \[ \renewcommand{\arraystretch}{1.6} \begin{array}{rcr@{\!\!\;\,}l} \Afbc(\sqrt{s} = 91.235 \, {\rm GeV}) &=& &0.0659\,\, \pm\,\, 0.0094\, (stat)\,\, \pm\,\, 0.0035\, (syst) \\ \Afbb (\sqrt{s} = 91.235 \, {\rm GeV}) &=& &0.0762\,\, \pm\,\, 0.0194\, (stat)\,\, \pm\,\, 0.0085\, (syst) \\ \Afbc(\sqrt{s} = 89.434\, {\rm GeV}) &=&-&0.0496\,\, \pm\,\, 0.0368\, (stat)\,\, \pm\,\, 0.0053\, (syst) \\ \Afbb(\sqrt{s} = 89.434\, {\rm GeV}) &=& &0.0567\,\, \pm\,\, 0.0756\, (stat)\,\, \pm\,\ 0.0117\, (syst) \\ \Afbc(\sqrt{s} = 92.990\, {\rm GeV}) &=& &0.1180\,\, \pm\,\, 0.0318\, (stat)\,\, \pm\,\, 0.0062\, (syst) \\ \Afbb(\sqrt{s} = 92.990\, {\rm GeV}) &=& &0.0882\,\, \pm\,\, 0.0633\, (stat)\,\, \pm\,\, 0.0122\, (syst) \\ \end{array} \] The combination of these results leads to an effective electroweak mixing angle of: SINEFF = 0.2332 \pm 0.0016

Publication details
Download http://hal.in2p3.fr/in2p3-00002469/en/
Publisher HAL - CCSD
Repository INRIA a CCSD electronic archive server based on P.A.O.L (France)
Keywords Physics/High Energy Physics - Experiment
Type peer-reviewed article
Relation http://hal.inria.fr/docs/00/00/60/68/PDF/democrite-00002469.pdf