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

Chapter 6: Event Selection 191
smearing needed in Monte Carlo to reproduce the data. Figure 6.14 shows the fitted
width vs. the smearing parameter separately for Z events with both muons in the
barrel (left) and both in the endcap (right).
Figure 6.13: Muon momentum scale (left) and additional smearing (right) needed in
the Monte Carlo simulation to reproduce data, using all Z → µµ events in the sample.
Red lines denote the fitted peak position (width) and its statistical uncertainty in
data. Black points denote the fitted peak position (width) from Monte Carlo.
Table 6.12 shows the values of the parameters C1 and C2 separately for the case of
all Z events and for Z events with both muons in the barrel and both in the endcap.
We see that the muon momentum scale and resolution in data are consistent between
the barrel and the endcap within statistical errors. Instead of correcting our mea-
surement with these values, we take them as uncertainties on the muon momentum
scale and resolution and determine their effect on the Z → µµ event acceptance.