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

Chapter 4: Data Collection and Event Reconstruction 148
one high-pT combined muon 21 . In these events, an inner detector track (the ‘probe’)
is searched for using a set of criteria such as to ensure that it comes from a Z → µµ
decay 22 . The combined muon reconstruction efficiency is defined as the fraction of
probe tracks that can be matched to a combined muon. Figure 4.15 illustrates the
tag-probe method using Z → µµ events.
Figure 4.15: Schematic illustration of the tag-probe method using a Z → µµ event.
The criteria used to select the tag muon and probe track are listed is Table 4.6.
Note that only events containing at least one tag and at least one probe are used in
the efficiency estimation.
114 events pass the selection criteria, containing 157 probe tracks. Matching the
probes with combined muons using the condition ∆R