Determination of the leptonic branching ratios of the Z

Research output: Contribution to journalArticleResearch

109 Citations (Scopus)


The ratios of the numbers of Z bosons decaying to e+e-, μ+μ- and τ+τ- pairs to the number decaying to hadrons have been measured. The branching ratios and partial widths for each channel were determined and found to be equal, consistent with lepton universality. The mean leptonic branching ratio was found to be 0.0321 ± 0.0013 and the leptonic partial width to be 85.4 ± 5.3 MeV. The partial widths for hadronic decays and for invisible decays were deduced to be 1833 ± 116 MeV and 569 ± 92 MeV, respectively. The number of light neutrino types, assuming only the standard model value for the ratio Θe Θv, was found to be 3.35 ± 0.41. © 1990.
Original languageEnglish
Pages (from-to)399-408
JournalPhysics Letters B
Issue number3
Publication statusPublished - 11 Jan 1990


Dive into the research topics of 'Determination of the leptonic branching ratios of the Z'. Together they form a unique fingerprint.

Cite this