Oblique Corrections to the W Width

Abstract

The lowest-order expression for the partial W width to eν, Γ(W → eν) = GµMW3 /(6π √ 2), has no oblique radiative corrections from new physics if the measured W mass is used. Here Gµ = (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 Γtot(W) is also expected to lack oblique corrections from new physics, so that Γtot(W)/Γ(W → eν) = 3 + 6[1 + {αs(MW )/π}]. Present data are consistent with this prediction.