Abstract
We have measured the mass of the Z boson to be 91.14±0.12 GeV/, and its width to be 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.
- Received 12 October 1989
DOI:https://doi.org/10.1103/PhysRevLett.63.2173
©1989 American Physical Society