Role of sin2θW(mZ) at the Z0 peak

The possible role of the anti Manti S parameter sin2θW(mZ) in discussing physics at the Z0 peaks is outlined. A radiative correction Δr (the analogue or Δr), which links directly sin2θW(mZ) to mZ, is introduced and evaluated in the standard model. Assuming 60 GeV<mt<200 GeV, 10 GeV<mH<1 TeV, employing Δr and mz=91.12±0.16 GeV leads to an accurate determination sin2θW(mZ)=0.2328±0.0012±0.0022 (the first error is due to δmZ and the second reflects the mt, mH uncertainty). It is interesting to note that this result is consistent with the simplest SUSY GUTs prediction. Accurate values for αi(mZ) (i=1, 2) are also given. Constraints due to gauge invariance in defining effective weak interaction angles are discussed. (orig.)