Oblique Corrections To The W Width
The lowest-order expression for the partial $W$ width to $e ν,~Γ(W \to e ν) = G_μM_W^3 /(6 π\sqrt{2})$, has no oblique radiative corrections from new physics if the measured $W$ mass is used. Here $G_μ= (1.16639 \pm 0.00002) \times 10^{-5}$ GeV/$c^2$ 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$/c^2$, one expects $Γ(W \to e ν) = (224.4 \pm 2.3)$ MeV. The total width $Γ_{\rm tot}(W)$ is also expected to lack oblique corrections from new physics, so that $Γ_{\rm tot} (W)/ Γ(W \to e ν) = 3 + 6 [1 + \{α_s (M_W)/π\}]$. Present data are consistent with this prediction.
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