H4l with 8.8.0

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H?4l with 8.8.0

• L. R. Flores, B. Mellado, S. Paganis, W. Quayle,
  Sau Lan Wu

University of Wisconsin-Madison Higgs Working
Group Meeting 15.12.04
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Outline

• Introduction
• Sample/Reconstruction
• Generator level quantities
• Reconstruction
• Final comments

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Introduction

• Dominant discovery channel for m(H)gt200GeV
• Relatively clean signature
• 4 lepton events
• Choose pairing compatible with a Z boson, one
  close to Z mass
• Cut on m(Zi), m(H).

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Sample/Reconstruction

• Full simulation, DC2-type, Geant 4
• 8.0.7 sim, 8.8.0 digi and reco.
• 5x5 cell clusters
• Realistic noise
• mH 130, 150, 180, 400, 500 GeV
• 4e, 4?, 2e2?
• TDR-like cuts and procedure
• Z1 lepton pair closest to Z mass.
  M12?Mass(Z1)
• Z2 best Z from remaining lepton candidates.
  M34 .
• Electrons calo tracking reco.

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Validation of generator-level quantities
150 GeV
Pt of leading and subleading leptons from Z1
from H.
mH 130 GeV
400 GeV
500 GeV
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Validation of generator-level quantities
150 GeV
M12, M34 for Z in H?4?
mH 130 GeV
180 GeV
500 GeV
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Validation of generator-level quantities
? for electrons and muons.
180 GeV
mH 130 GeV
400 GeV
500 GeV
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Validation of generator-level quantities
180 GeV
?H (black) and ?Z (gray).
mH 130 GeV
400 GeV
500 GeV
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Side notes

• EG block in CBNT 8.8.0 the matching track index
  is always -1, but tracking quantities are still
  present in 68 of clusters.
• There is a peak in the vertex-z distribution at
  around -36.19 mm

vertex z for combined muons mm
vertex z for combined muons mm
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Reconstruction efficiency

• Efficiencies
• Denominator leptons generated in each eta
  bin (or Pt bin).
• Numerator of those, how many found.
• Matching
• To determine if a given truth-particle has been
  found, we look for a lepton in a cone of ?R0.1
  around it.

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Reconstruction efficiency, vs Eta
Matching ?R lt 0.1
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Reconstruction efficiency, vs Eta
Matching ?R lt 0.1
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Reconstruction efficiency, vs Pt
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Reconstruction efficiency, vs Pt

• central region (?lt1.0)

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Reconstruction efficiency, vs Pt
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Reconstruction efficiency, vs Pt

• central region (?lt1.0)

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Mass resolution
Mass resolution for mH 150 GeV. NB No
kinematic fits applied
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DC1 / DC2 (130 GeV)

• Mass resolution for mH130GeV

DC1 Athena 6.0.3 for 4e, 7.0.2 otherwise DC2
This results In both cases, no kinematic fits.
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Mass resolution vs mH
sm GeV
sm GeV
sm GeV
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Relative resolution (sm /mH)
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Summary and plans

• DC2 in general good shape.
• A few glitches, some not in 9.0 (e.g.
  trkmatch-1).
• Mass resolution increase of about 50 wrt DC1,
  but more work is needed (5x5 calibration, track
  matching, study calo-only reco,).
• Next
• BG (main source already reconstructed),
• 5x5 calibration,
• 9.X.