Accurate determination of sin2 theta -circumflexW(mZ).

Abstract

A radiative correction $\ensuremath{\Delta}{\stackrel{^}{r}}_{W}$ linking directly the -MS (modified minimal-subtraction scheme) parameter ${sin}^{2}{\stackrel{^}{\ensuremath{\theta}}}_{W}({m}_{Z})$ to ${G}_{\ensuremath{\mu}}$, $\ensuremath{\alpha}$, and ${m}_{W}$ is introduced. Its dependence on ${m}_{t}$ and ${m}_{H}$ is very weak. Employing ${m}_{W}=80.11\ifmmode\pm\else\textpm\fi{}0.31$ GeV (obtained from the direct and ${R}_{\ensuremath{\nu}}$ measurements of $\frac{{m}_{W}}{{m}_{Z}}$ in conjunction with ${m}_{Z}$) and allowing the range $78\ensuremath{\le}{m}_{t}\ensuremath{\le}200$ GeV, $10 \mathrm{GeV}\ensuremath{\le}{m}_{H}\ensuremath{\le}1 \mathrm{TeV}$ leads to ${sin}^{2}{\stackrel{^}{\ensuremath{\theta}}}_{W}({m}_{Z})=0.2327\ifmmode\pm\else\textpm\fi{}0.0018\ifmmode\pm\else\textpm\fi{}0.0007$ (the first error arises from ${m}_{W}$, the second reflects the ${m}_{t}$,${m}_{H}$ uncertainty), in very good agreement with the corresponding value ${sin}^{2}{\stackrel{^}{\ensuremath{\theta}}}_{W}({m}_{Z})=0.2327\ifmmode\pm\else\textpm\fi{}0.0012\ifmmode\pm\else\textpm\fi{}0.0021$ 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.