UvA-DARE ( Digital Academic Repository ) Measurement of the forward-backward asymmetry of charm and bottom quarks at the $ Z $ pole using \ ( D ^ { * ^ \ pm } \ ) mesons

The forward-backward asymmetries for the processes e+e ---, e6 and e+e ~ bb at the Z resonance are measured using identified D *+ mesons. In 905,000 selected hadronic events, taken in 1991 and 1992 with the DELPHI detector at LEP, 4757 D *+ ~ D~ + decays are reconstructed. The e and b quark forward-backward asymmetries are determined to be: c6 AF/~ = 0.077 • 0.029 (stat) 40.012 (sys) , A~B = 0.059 40.062 (stat) 40.024 (sys) . Constraining the b asymmetry to the value measured by DELPHI using independent analyses, the charm asymmetry is determined to be: FB = 0.068 40.027 (stat) 40.011 (sys) . This result corresponds to an effective electroweak mixing angle measured using charm quark events of: sin ~ AZePt = 0.2307 40.0062 (stat) 40.0026 (sys)