A measurement of the forward–backward asymmetry of e+e−→ccˉ and e+e−→bbˉ 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 andb quarks at the Z resonance are determined to be: AcFB(s√=91.235GeV)=0.0659±0.0094(stat)±0.0035(syst)AbFB(s√=91.235GeV)=0.0762±0.0194(stat)±0.0085(syst) AcFB(s√=89.434GeV)=−0.0496±0.0368(stat)±0.0053(syst)AbFB(s√=89.434GeV)=0.0567±0.0756(stat)±0.0117(syst) AcFB(s√=92.990GeV)=0.1180±0.0318(stat)±0.0062(syst)AbFB(s√=92.990GeV)=0.0882±0.0633(stat)±0.0122(syst) The combination of these results leads to an effective electroweak mixing angle of: sin2θlepteff=0.2332±0.0016
Abreu, P. ; Cortina Gil, Eduardo ; DELPHI Collaboration ; et. al. Measurement of the forward backward asymmetry of c and b quarks at the Z pole using reconstructed D mesons. In: European Physical Journal C. Particles and Fields, Vol. 10, no.2, p. 219-237 (1999)