Measurement of the effective weak mixing angle by jet-charge asymmetry in hadronic decays of the Z boson

The coupling of the Z boson to quarks is studied in a sample of about 3.5 million hadronic Z decays collected by the L3 experiment at LEP from 1991 to 1995. The forward–backward quark charge asymmetry is measured by means of a jet charge technique. From the measured asymmetries, the effective weak mixing angle is determined to be sin2θW=0.2327±0.0012(stat.)±0.0013(syst.).