Oblique Corrections To The W Width

The lowest-order expression for the partial $W$ width to $e \nu ,~\Gamma (W \to e \nu) = G_\mu M_W^3 /(6 \pi \sqrt{2})$, has no oblique radiative corrections from new physics if the measured $W$ mass is used. Here $G_\mu = (1.16639 \pm 0.00002) \times 10^{-5}$GeV\mathrm{/}$c^2$ is the muon decay constant. For the present value of $M_W=(80.14\pm 0.27)$ GeV/$c^2$, and with $m_t=140$ GeV$\mathrm{/}{c}^2$, one expects $\mathrm{\Gamma }(W\to e\nu )=(224.4\pm 2.3)$ MeV. The total width ${\mathrm{\Gamma }}_{\mathrm{t}\mathrm{o}\mathrm{t}}(W)$ is also expected to lack oblique corrections from new physics, so that $\Gamma_{\rm tot} (W)/ \Gamma (W \to e \nu) = 3 + 6 [1 + {\alpha_s (M_W)/\pi }]$. Present data are consistent with this prediction.