L3 Tracking efficiencies on Zs, rejection

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L3 Trackingefficiencies on Zs, rejection

• Daniel Whiteson
• LBL

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Matching tracks
Select Zs from peak of di-EM mass Reconstruct
event with L3TGlobalTracker Match tracks to
electrons
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Efficiency
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Recent runs, gt150k
80 efficient in central region!
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Inefficiencies

• What is the contribution from
• Clustering inefficiencies
• Algorithm inefficiencies
• Matching inefficiencies

To determine clustering contribution, take path
of electron and look for nearest cluster at each
layer of the CFT. This removes algorithmic
problems or deficiencies.
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Electron-cluster residual
Df between electron and nearest cluster on CFT
layer
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2
3
4
5
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7
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Widths of central peaks are 0.01 radians
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Clustering
Figure of merit is the number of clusters within
tolerance per electron
Global layer of missing cluster
Df lt 0.025
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Efficiency
With matched track
Without matched track
94 efficient for electrons with 7 or 8 clusters
within eta of 1.2
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Rejection on 160588