Oblique Corrections to the W Width

Abstract

The lowest-order expression for the partial W width to eν, Γ(W → eν) = G_µM_W³ /(6π √ 2), has no oblique radiative corrections from new physics if the measured W mass is used. Here G_µ = (1.16639 ± 0.00002) × 10⁻⁵ GeV/c² is the muon decay constant. For the present value of MW = (80.14±0.27) GeV/c², and with mt = 140 GeV/c², one expects Γ(W → eν) = (224.4 ± 2.3) MeV. The total width Γ_tot(W) is also expected to lack oblique corrections from new physics, so that Γ_tot(W)/Γ(W → eν) = 3 + 6[1 + {α_s(M_W )/π}]. Present data are consistent with this prediction.