Precise measurement of the left-right cross section asymmetry in Z boson production by e+e- collisions

摘要

We present a precise measurement of the left-right cross section asymmetry (A_{LR}) for Z boson production by \ee collisions. The measurement was performed at a center-of-mass energy of 91.26~GeV with the SLD detector at the SLAC Linear Collider (SLC). The luminosity-weighted average polarization of the SLC electron beam was (63.0\pm1.1)\%. Using a sample of 49,392 \z0 decays, we measure A_{LR} to be 0.1628\pm0.0071(stat.)\pm0.0028(syst.) which determines the effective weak mixing angle to be \swein=0.2292\pm0.0009({\rm stat.})\pm0.0004({\rm syst.}).}