Measurement of the Z boson cross-section in - Harvard University ...

Chapter 8: Properties of Z bosons and measurement of Z → µµ cross-section 227
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Data 2010( s = 7 TeV)
Z → µ µ
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∫L
dt = 331 nb
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Pixel hits/track
Figure 8.4: Pixel hits on inner detector tracks matched to muon spectrometer tracks
for signal Monte Carlo and data after the full Z selection.
with the combined muon track, while Figure 8.5 displays the number of SCT and
TRT hits on the track. We see good agreement between the data and the Monte
Carlo expectation in all three plots.
Kinematic distributions
Figure 8.6 shows kinematic distributions (pT , η and φ) for muons from the decay
of the Z candidates.
Figure 8.7 shows the muon pT versus dimuon invariant mass at two different stages
of the Z selection cuts: after the muon pT cut (left) and after the isolation cut (right)
on the decay muons. We see that the Z events are concentrated in the expected band
in this 2D phase space. As expected, the isolation cut removes a number of events