MET and NADA STUDIES

1
MET and NADA STUDIES

• Studies of the Coarse Hadronic contribution to
  the missing ET
• Used data processed with p13.04.00
  (runs 165589 ?169002)
• Hot cells in p13.04
• Cells distributions in the CH
• MET with and without CH contribution

G. Bernardi and S. Trincaz-Duvoid LPNHE-Paris
2
Number of hot cells
number of hot cells
runs 165
runs 166
runs 168
Number of positive hot cells over 1000 events of
a root-file Abscissa 1 entry per root-file Red
hot cells in all layers Green hot cells in the
CH (layers 15-16-17) Blue hot cells outside the
CH
runs 169
root file
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Hot cells distributions in the CH
Example of 1000 evts on run 168987
i?
PT
Hot cells at low PT
layer
i?
Hot cells not searched for in layer 15 between 1
and 5 GeV
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Effect of the CH on the missing ET
Mean value of MET distribution (GeV)
runs 166
runs 165
runs 168
runs 169
Root-file
MET calculated with 1000 evts of a root file.
Cut on cells at 0.1
GeV Blue all layers - Red without CH
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Origin of the discrepancy cells distribution in
the CH
PT of cells in the CH and out of the
CH. Accumulation of cells between 0.2 and 1 GeV
In CH
GeV
1
2
0.1
Out of CH
GeV
1
2
0.1
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Effect of a cut on cells energy on MET
Ecells gt 0
Ecells gt 0.1 GeV
Mean of MET distributions (GeV) for 1000 evts of
a root file Blue all layers - Red without
CH Cut on cells energy differ
Ecells gt 0.3 GeV
Ecells gt 0.5 GeV
If Ecells gt 1 GeV the CH stops to deeply degrade
MET. Problem mainly due to cells below 1 GeV
Ecells gt 0.7 GeV
Ecells gt 1 GeV
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Effect of a cut on cells energy on METx
0
0
Ecells gt 0
Ecells gt 0.1 GeV
Mean of METx distributions (GeV) for 1000 evts of
a root file Blue all layers - Red without
CH Cut on cells energy differ
0
0
Ecells gt 0.3 GeV
Ecells gt 0.5 GeV
0
0
If Ecells gt 1 GeV the CH stops to deeply degrade
METx.
Ecells gt 0.7 GeV
Ecells gt 1 GeV
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Effect of a cut on cells energy on
METy
0
0
Ecells gt 0
Ecells gt 0.1 GeV
Mean of METy distributions (GeV) for 1000 evts
of a root file Blue all layers - Red
without CH Cut on cells energy differ
0
0
Ecells gt 0.3 GeV
Ecells gt 0.5 GeV
0
0
Another problem subsisting at 1 GeV METy remains
always negative when CH included
Ecells gt 0.7 GeV
Ecells gt 1 GeV
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A hot zone in layers 16-17
Ecellgt1GeV Layer 16 17
PTsin(?)
A hot zone in i? explains the negative METy even
with cells energy above 1 GeV.
METy all layers
ltgt-0.72 rms8.2
accumulation
i?
METy no CH
ltgt-0.39 rms8.2
ltgt-0.31 rms8.0
METy all layers In layer 16 17,
no 14lti?lt22 . 46lt i? lt54
Even with a cut at 1 GeV on cells,
hot zones remain, degrading MET
10
Decrease hot cells threshold in CH
i?
i?
i?
Threshold 0.6 GeV
Threshold 1 GeV
Threshold 0.8 GeV
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Decrease hot cells threshold in CH
MET all layers but HC thr. at 0.8 GeV
MET all layers
MET no CH
ltgt9.60 rms7.4
ltgt8.73 rms7.4
ltgt9.59 rms7.4
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Conclusion

• The CH is a source of MET degradation
• In CH cells below 1 GeV degrade the MET
  distribution. Need to clean these cells
• Working on it (t42 algorithm will come soon)
• But even after cleaning cells below 1 GeV, some
  problems like hot region remain and will have to
  be solved.