Measurements of the decay of the Z^0 into lepton pairs

We report on a measurement of the processes e^+e^-->e^+e^-, e^+e^-->μ^+μ^-, and e^+e^-->τ^+τ^- near the Z^0 pole. On the basis of 163 e^+e^-, 101 μ^+μ^- and 87 τ^+τ^- events we obtain Γ"e"e=89+/-4+/-4 MeV, Γ"μ"μ=85+/-9+/-6 MeV and Γ"τ"τ=87+/-10+/-8 MeV, compati...
Ausführliche Beschreibung

We report on a measurement of the processes e^+e^-->e^+e^-, e^+e^-->μ^+μ^-, and e^+e^-->τ^+τ^- near the Z^0 pole. On the basis of 163 e^+e^-, 101 μ^+μ^- and 87 τ^+τ^- events we obtain Γ"e"e=89+/-4+/-4 MeV, Γ"μ"μ=85+/-9+/-6 MeV and Γ"τ"τ=87+/-10+/-8 MeV, compatible with the standard model. Combining these with our previous results on hadronic Z^0 decays, we find a hadronic width Γ"h"a"d=1787+/-81+/-90 MeV and an invisible width Γ"i"n"v=552+/-85+/-71 MeV. Ausführliche Beschreibung