deletions | additions       diff --git a/Measurements at the Z pole.tex b/Measurements at the Z pole.tex  index 73b2408..f52b423 100644  --- a/Measurements at the Z pole.tex  +++ b/Measurements at the Z pole.tex 
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with a common systematic error of 0.007. The experimental error was dominated by the statistics of leptonic decays; selection systematics will tend to decrease with statistics. The remaining systematics are related to the t-channel contribution in the electron channel (this could be removed by using the muon channel only) and to the detailed modelling of final state radiation or emission of additional lepton pairs: here theory should be considerably helped by the large sample of leptonic Z decays available for the study of these rare processes. \\   {\em We consider that a relative precision of $10^{-4}$ is a reasonable target goal for the ratio of the hadronic to leptonic partial widths at TLEP-Z }.  This measurement of the peak hadronic cross-section is already dominated by theoretical systematics related to the understanding of the low angle Bhabha cross-section. It is a measurement of great importance as it determines the Z invisible width, a direct test of the unitarity of the PMNS matrix -- or of the existence of sterile neutrinos. The experimental conditins at TLEP will be adequate to inprove the experimental uncertainty but a considerable effort will have to be invested in the theoretical calculations to make this measurement worthwhile.