H 2m1e X Analysis

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• H ? 2m1e X Analysis

• OUTLINE
• Motivations.
• 2m1e Signal estimate.
• Background estimate.
• Future Plan.

Azeddine Kasmi Bob Kehoe Southern Methodist
University Thanks to Hong Ma
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Motivations and Data Sets

• The sensitivity to electron identification cuts
  gives more acceptance to 1e than 2.
• However, the Background is higher.
• Current results H ? 2m 1e X
• At this talk, the emphasis is on cluster-based
  approach (to help in forward region).
• Ultimately expect to use with a track based
  approach (Julia Hoffman).
• The thrust of this analysis is to estimate 2m 1e
  X signal (SB).
• This analysis was done on AOD release 13.0.40
• Signal Sample 5300, MH 130 GeV , 9950 events
• Background
• ttbar Sample5211.ttbarMcAtNLO4Leptons. 78850
  events
• Zbb Sample 5176 Not yet available in release
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• WZ Sample 6359.Jimmy. 14750 events
• ZZ Sample 5931 MCatNLO.Jimmy 20000 events

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Isolation Missing ET
Electron isolation
ETmiss
ZZ WZ Higgs ttbar
ZZ WZ Higgs ttbar
Muon isolation
ZZ WZ Higgs ttbar

• ETmiss lt 20 GeV
• etcone20/Pt lt 0.2

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Signal and Background afterPt cuts ETmiss
Isolation (etcone20/et)
DATA NOT AVAILABLE IN RELEASE 13
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The unfound Electron might be seen as a jet
Remove jets within dR lt 0.2 From the isolated
Medium electron
In the event of where ETmiss lt 20 GeV 1
isolated Medium electron and 2 isolated Muons
are reconstructed With Pt gt 10 GeV
Jet Candidate (i.e. a potential electron
reconstructed with Jet Algorithm C4)
Does the jet candidate match the unfound truth
electron
Most reconstructed jets are actually electrons in
this sample.
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Jets vs Jet candidates in Higgs sample
Jets Jet candidates
This tail has not been seen in 12.0.6 ????
Higher number of jets per events is due to the
electrons seen as jets
Pt of first leading jet (No truth match)
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Kinematics of matched jet candidate
79 of jet candidate match the unfound truth
electron There are 468 matches in DR lt 0.2 e
468/587 79
DR between a jet candidate and the unfound truth
electron in Higgs
The H ? 4l sample was restricted to h lt 2.7
Pt of the unfound truth electron
Pt of the jet candidate that matched the unfound
truth electron
Eta of jet candidate matched to the unfound Z
electron.
Leading jet usually matches unfound electron
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Pt Resolution in two Pt ranges
RMS 0.47
RMS 0.24
Pt of unfound truth Electron lt 20 GeV
Pt of unfound truth Electron gt 20 GeV
May use a Pt threshold to improve the resolution
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Find the on shell Z in Higgs sample ( H ? Z Z
)
Z is from 2 muons
Among all 4 objects If the electron or the
first leading jet candidate have a leading Pt.
So the on shell Z is from the electron and
first leading jet candidate. Otherwise, The on
shell Z is from the 2 muons.
Mmm
Z is from Electron and a jet candidate
Zmumu or Zejc should be between 80-110 GeV is
added as cut for the following slide.
Mejc
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Require the matching
Matching cleans the Z ? ee ID cuts on jets will
do the same hopefully
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The mass of 4 objects2 muons 1 electron
first leading jet ( No ID Cuts)
Require matching
ZZ
Higgs
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Results

• Total Selection
• 1)PT3l gt 10 GeV
• 2)Isolation etcone20/PT ( lt 0.2 )
• 3)ETmiss lt 20 GeV,
• 4)MZ within the interval (80 - 110 GeV)
• In Higgs sample
• 330 events passed cuts , e 7
• NH 0.07 3.125 fb 10 fb-1 2.2 events
• Particle ID cuts on jet candidate should improve
  efficiency.
• Also, The actual sample have an eta cut on
  leptons. The efficiency and S/B are compromised.
• In ttbar sample
• 10 events passed cuts , e 0.03
• Nttbar 0.03 8000 fb 10 fb-1 24
• In WZ sample
• 79 events passed cuts , e 2
• NWZ 2 190 fb 10 fb-1 38
• In ZZ sample

So far S B ttbar 1 11 WZ
1 17 ZZ 1 20
(worse!)
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To do list

• Try to use the Back Navigation on ESD to get the
  EM fraction to use as an ID cut on the jet
  candidates.
• Use the Topo cluster ( 3D Algorithm ) to improve
  the resolution ( in progress )
• Try to find a way to get an estimate for the Zbb
  background ( may be go back to 12.0.6 AANT)

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Find the on shell Z in ttbar sampleif El_Pt is
the leading or the jet candidate then Z is e
jet candidate otherwise Z is from the muons
BACK UP
Z is from 2 muons
Z is from Electron and a jet candidate
Quite a good cut in ttbar
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Find the on shell Z in WZ sampleif El_Pt is the
leading or the jet candidate then Z is e jet
candidate otherwise Z is from the muons
BACK UP
Z is from Electron and a jet candidate
Z is from 2 muons
As expected Z is from mu mu
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Find the on shell Z in ZZ sampleif El_Pt is the
leading or the jet candidate then Z is e jet
candidate otherwise Z is from the muons
BACK UP
Z is from Electron and a jet candidate
Z is from 2 muons
This cut would inefficient in the ZZ case