8/26/02 d0 calorimeter task force stephanie beauceron lpnhe - paris 1 offline zero suppression aim:...
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8/26/02D0 Calorimeter Task Force
Stephanie BeauceronLPNHE - Paris
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Offline zero suppression
Aim:Understand the huge value of Missing ET at 1.5
Principally two runs have been studied from p11:- 158541 1.5 run- 157581 2.5 runOn QCD and Bias (zero bias and minimum bias) events
A method to simulate the cut at 2.5 on 1.5 has been developed Look at the MET resolutions for the QCD and Bias events
8/26/02D0 Calorimeter Task Force
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Determination of the sigma value
On a file of 1.5:•Distribution of cell energy:-by type of preamplifier -by 4 zones of the calorimeter (-32ieta<-15; -15ieta<0;0<ieta 15;15<ieta32)
-And by layer.•Look for the maximum of the distribution,1.5=bin(20% of the maximum)
Value of 1.5
Example of cuts
1.5 sigma cut at 2.5 sigma2.5 sigma
Met and Set at 1.5 and at 2.5 on bias events
1.5 sigma2.5 sigma
Mean RMS 3.6 2.512.9 8.2
Mean RMS 1.1 3.4 1.8 10.3
Mean RMS -0.9 2.6 -3.2 8.8
Mean RMS 30.3 13.9202.6 40.6
Met is 4 times more importantin run 1.5.In run 1.5, there is 6 times more energy than in run 2.5.
Mean RMS 7.3 5.3 9.0 6.9
Mean RMS 1.6 6.2 1.8 7.7
Mean RMS -1.5 5.7 -1.1 7.0
Mean RMS 76.9 29.8 70.5 28.9
Consequences of cuts on MET and SET
Mean RMS 3.6 2.5 5.4 4.8
Mean RMS 1.2 3.3 -1.4 5.6
Mean RMS -1.2 2.4 -1.6 3.9
Mean RMS 25.7 9.1 26.0 11.9
1.5 sigma cut at 2.5 sigma2.5 sigma
Zero Bias events QCD events
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Met resolutions for QCD events
Run 1.5
Run 1.5 cut at 2.5
Run 2.5Slope 0.940
Slope 0.061
Slope 1.122
Slope 0.064
Slope 0.703
Slope 0.022
Met value at 1.5 is understandable
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Met/Set resolution for QCD events
Run 1.5
Run 1.5cut at 2.5
Run 2.5Slope 0.0035
Slope 4.10-6 Slope 0.0015
Slope 0.0011
Slope -0.0005
Slope -0.0005
Met is varying as Set
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Met resolution for Bias events
Run 1.5
Run 2.5
Run 1.5 cut at 2.5
Slope 0.934
Slope 0.875Slope 0.030
Slope 1.618
Slope 0.083
Slope 0.137
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Met/Set resolution for Bias events
Run 1.5
Run 1.5 cut at 2.5
Run 2.5
Slope –4x10-5
Slope –0.001
Slope –0.001
Slope 0.0009
Slope 0.0032
Slope 0.0077
On run 1.5, Met is varying as Set
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A lot of Negative Energy…
Run 1.5 Run 2.5
On bias events:
8/26/02D0 Calorimeter Task Force
Stephanie BeauceronLPNHE - Paris
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Conclusion• The method to cut on sigma value is valid• For a cut at 1.5 we have a MET greater than 10 GeV on Bias events• MET is varying as Sqrt(Set) from QCD events• Still to look at the negative energy cells…
1.5 1.7 2 2.5
Zero bias events