An improved determination of the ratio of W and Z masses at the CERN p collider

Abstract The W and Z bosons masses, m w and m z , are measured using saing samples of W→ev and Z→e + e − decays observed in p p collisions at √ s =630 GeV. The ration is found to be m w m z =0.8813±0.0036 ± 0.0019 . This gives a value sin 2 θ w = 0.2234 ± 0.0064 ± 0.0033, and in combination with precise m z measurements from LEP yields m w =80.35±0.33±0.17 GeV. This result is in good agreement with other experiments, and with the standard model for a top quark mass lighter than 250 GeV.