Measurements of Z-boson resonance parameters in $e^{+}$$e^{\mathrm{-}}$ annihilation

We have measured the mass of the Z boson to be 91.14±0.12 GeV/$c^2$, and its width to be ${2.42}_{\mathrm{-}0.35}^{+0.45\mathrm{}}$ GeV. If we constrain the visible width to its standard-model value, we find the partial width to invisible decay modes to be 0.46±0.10 GeV, corresponding to 2.8±0.6 neutrino species, with a 95%-confidence-level upper limit of 3.9.