The effect of the Higgs boson on the threshold cross-section in W-pair production

We investigate the uncertainty induced by the Higgs-boson mass on the determination of mw from the LEP-2 run near the threshold for W-pair production. For a light Higgs boson the Yukawa interaction between the two slowly-moving W bosons gives rise to a correction of close to 1% to the total cross-section. This corresponds to a 15 MeV shift in the deduced W mass for a Higgs-boson mass of 60 GeV. We present a simple approximation for this correction and discuss its validity.