Accurate determination ofsin2θ^W(mZ)

A radiative correction $\Delta {\hat{r}}_W$ linking directly the ―MS (modified minimal-subtraction scheme) parameter ${sin}^2{\hat{\theta }}_W\left(m_Z\right)$ to $G_{\mu }$, $\alpha$, and $m_W$ is introduced. Its dependence on $m_t$ and $m_H$ is very weak. Employing $m_W=80.11\mathrm{}\pm 0.31$ GeV (obtained from the direct and $R_{\nu }$ measurements of $\frac{m_W}{m_Z}$ in conjunction with $m_Z$) and allowing the range $78\le m_t\le 200$ GeV, $10 \mathrm{GeV}\le m_H\le 1 \mathrm{TeV}$ leads to ${sin}^2{\hat{\theta }}_W\left(m_Z\right)=0.2327\mathrm{}\pm 0.0018\pm 0.0007$ (the first error arises from $m_W$, the second reflects the $m_t$,$m_H$ uncertainty), in very good agreement with the corresponding value ${sin}^2{\hat{\theta }}_W\left(m_Z\right)=0.2327\mathrm{}\pm 0.0012\pm 0.0021$ obtained from $m_Z$. Implications for the $Z^0$ asymmetries and the possible use of the $m_W$ determination in extensions of the standard model involving Higgs triplets are outlined.