A first look at photon longitudinal weights using DC2 MC

1
A first look at photon longitudinal weights using
DC2 MC

• Karina Loureiro, Stathes Paganis, Sau Lan Wu
• University of Wisconsin - Madison
• Higgs Working Group
• September 1st, 2004

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Outline

• Motivation
• Results from longitudinal weights applied to
  electrons (8.0.58.5.0)
• Test of longitudinal weights applied
  (preliminary) to 50 GeV photons (8.0.58.3.0)
• Photon longitudinal weights obtained using 50 GeV
  photons (8.0.58.3.0) (all ?s)
• Photon longitudinal weights applied to
  (8.6.08.6.0) (most likely in the future)
• Plans

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Motivation

• At the core of many analyses there are
  electrons and photons. The understanding of the
  calorimeter response and their correct weighting
  are paramount to the success of the analyses.

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On Electrons ...
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Electron Longitudinal Weights (Review)

• Following previous strategy, we define the
  reconstructed energy (EM barrel and end-cap) as
• Erec ? (b W0EpresE1E2W3E3)
• We extract the free parameters in 100 bins of ? (
  ? lt 0.025)
• Apply constants at the CBNT ntuple level (i.e.,
  E1 eg_e1, etc.)

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Electron Resolution
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Electrons on Photons ...
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Electron Longitudinal Weights Applied to Photons

• Effects on non-converted photons
• 8.0.5 official simulation and digitization.
  Reconstruction with 8.3.0 (used for converted and
  non-converted alike).
• DC2 longitudinal weights applied
• Effects on converted photons
• Conversions identified using the conversion block
  and the egtrkmatchnt_TP
• Applied DC2 longitudinal weights

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Electron Longitudinal Weights Applied to
Non-converted Photons
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Electron Longitudinal Weights Applied to
Non-converted Photons by ? Regions
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Electron Longitudinal Weights Applied to
Non-converted Photons (cont.)

• Observe that the end-cap photons (red) need
  almost no corrections.
• There are other sweet regions where it would
  seem that the photons are doing just fine.
• Overcorrection (perhaps) due to fitting of tail.

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Electron Longitudinal Weights Applied to
Converted Photons (5x5 cluster size)
50 GeV photons
After e- corrections
Before e- corrections
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Electron Longitudinal Weights Applied to
Converted Photons by ? regions
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Electron Longitudinal Weights Applied to
Converted Photons by ? regions (cont.)
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Electron Longitudinal Weights Applied to
Converted Photons (3x7 cluster size)
After e- (scale) correction
Before e- (scale) correction
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Photons on Photons ...
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Photon Longitudinal Weights Applied to
Non-converted Photons
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Photon Longitudinal Weights Applied to
Non-converted Photons
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8.6.0 all the way

• Events generated, simulated and reconstructed
  using offline release 8.6.0 with electron
  longitudinal weights turned on
• Electron constants applied only to identified
  conversions and removed from non-converted
  photons in combination with converted photon
  weights

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Results Plans

• Photon energies need to be corrected with photons
• Electron corrections are not apt for all
  photons
• Clustering choice has a strong effect on photon
  energy reconstruction
• Need a range of photon energies to obtain the
  parameters to appropriately do the fit
• Must integrate MCTruth information (a.k.a.
  Geant4) in order to tune the conversion block
• Will apply two different set of constants for
  converted and non-converted photons
• We might need a different way of calculating the
  corrected photon energies