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Muon Performance in the 25 ns runs

Muon Performance in the 25 ns runs. Niels van Eldik, Peter Kluit MATF/MCP meeting 12 September 2013. Introduction. Look at the difference in Muon Performance for the 25 ns run and compare this to a 50 ns run. Data sets:

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Muon Performance in the 25 ns runs

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  1. Muon Performance in the 25 ns runs Niels van Eldik, Peter Kluit MATF/MCP meeting 12 September 2013

  2. Introduction Look at the difference in Muon Performance for the 25 ns run and compare this to a 50 ns run. Data sets: 25 ns data12_8TeV.00216432.physics_Muons.recon.DESD_ZMUMU.f507_m1246_f507 50 ns data12_8TeV.00200967.physics_Muons.recon.DESD_ZMUMU.r4056* Use the Z skim because the trigger conditions have changed; can compare Zs to Zs under different machine conditions Here a run with similar machine conditions is used (as proposed by Philipp Fleischmann)

  3. Z Tag and Probe efficiencies: 25 ns

  4. Z Tag and Probe efficiencies: 50 ns Very very similar at few per mille level within stats

  5. Z Tag and Probe Trigger efficiencies: 25 ns Quite similar but there were changes to trigger

  6. Z Tag and Probe Trigger efficiencies: 50 ns

  7. Muons from Zs isolation Mean Et cone 0.835 1.03 GeV There is slightly more energy Et collected around muon in the 25 nsec run. Ratio measured is 1.23. We need a calorimeter expert to tell us whether this is expected…

  8. Vertices in the two runs Difference in number vertices: about a factor of 2 due to the different bunch spacing (25 vs 50 ns). Inst Luminosity is pretty similar in these two runs (50ns/50ns = 0.937).

  9. MDT hits in the two runs Factor 3.68 more MDT hits in 50 ns Here one expects similar number of MDT hits due to the long MDT integration window. The ratio 50ns/25ns is 1.24. This is confirmed.

  10. RPC/CSC hits in the two runs RPC Ratio 50/25≈ 1.11 Expected ≈1 Time window is large and unchanged so and equals 64 counts… CSC (eta) Ratio 50/25 ≈ 1.45 Expected ≈1 Here also window is relatively large. Maybe not all is integrated…

  11. TGC hits in the two runs TGC Ratio ≈ 1.15 Expected naively* 0.5 because time window is short: only this BC… * See next slide for a further study TGC Previous and Next BC

  12. TGC hits in the two runs Above a Table specifying a all and single hit rates: a single hit is only assigned to one BC. It means that in the previous and next BC there is less rate than in the current BC. In the naïve model we assumed equal rates. So if one starts running at 25 ns one does NOT expect the rate to be divided by two wrt 50 ns because in the Next/Previous BC there is less rate (the ratio is about 1/3).

  13. Muon distribution for the ZpT > 20 GeV

  14. Muon distribution for the Z“third muon” pT < 20 GeV Note that there are more low pT muons in the 50 ns run: from pile up Plots normalized to number of Zs Factor ≈ 2 more low pT events in 50 nsec run Here one expects a factor 2 from 50/25 ns

  15. Conclusions Look at the difference in Muon Performance for the 25 ns run and compare this to a 50 ns run. Measurements for efficiencies comparing the two runs show a very similar muon identification efficiency. A reduction in the pile up background (in the 25 ns run) at low pT of a factor 2 is measured for CB and Tagged muons. This is expected. By selecting a run with similar condition also the backgrounds for the different detectors could be compared. All backgrounds in the MDT, RPC, CSC and TGC detectors are similar to or smaller than the 50 ns backgrounds. The CSC background is reduced a bit.

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