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Fake Lepton Rate
in EXO Seesaw Type III
Ezio Torassa (INFN Padova)
Andrea Gozzelino (INFN LNL)
January, 17th 2014
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Outline
• References
• General overview
• Objects definition
• Data sample and trigger
• Method details
• Manpower
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References
List of analyses using the method described in the rest of the talk.
Pointers to CADI lines and relevant ANs.
 No yet CADI line for PAS
 CMS AN-2013/135 in WorkingGroup: EXO, EXO non hadronic sub group
Title: Search for heavy lepton partners of neutrinos in pp collisions at 8 TeV, in the
context of Type III seesaw mechanism
http://cms.cern.ch:80/iCMS/jsp/openfile.jsp?tp=draft&files=AN2013_135_v2.pdf
Fake estimation is similar to the method used in the seesaw type III paper published in
2013 with 7 TeV data.
 http://cms.cern.ch/iCMS/analysisadmin/cadi?ancode=EXO-11-073
 http://arxiv.org/pdf/1210.1797v1.pdf
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General overview
STEP 1: Fake leptons rate
STEP 2: Apply FR to three leptons final state
FR(electron)
FR(muon)
FR(lepton) is medium value
Analysis objects (A)
Fake objects (F)
Fake contributions are backgrounds, in addition to SM processes and Dalitz events.
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Analysis objects (A) Fake objects (F)
Muon
< 50
< 0.2 cm
< 0.40
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Analysis objects (A) Fake objects (F)
Electron
Remove selection
< 0.60
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Data and triggers for FR
JetHT Primary Dataset (8 TeV data collected in 2012)
Single lepton prescaled triggers
MC samples and closure test
No MC control samples are used.
No closure test on MC samples is done.
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Step 1
 Events with at least one lepton (single lepton triggers thresolds);
 Opposite jet with momentum above 60 GeV;
 Missing transverse energy below 20 GeV;
 Transverse mass between missing transverse energy and lepton below 20 GeV;
Reduce contamination from electroweak processes (W and Z bosons)
 Filter on events with opposite sign same flavor leptons invariant mass in Z peak.
Reduce contamination from electroweak processes (Z boson)
(similar veto in the analysis)
Calculation is done on a sample with non prompt leptons (leptons not coming from
primary vertex); in the analysis Double Mu, Double Ele and MuEG primary dataset are
used. Selections are quite similar to what is applied in the analysis flow.
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Step 1 results
Muon
Electron
Pt > 10 GeV
Pt > 10 GeV
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Step 1 uncertainty
Conservative estimation based on references  50 %
Systematic source is dominant.
All 2012 data are taken in account.
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Step 2 results
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Manpower and future
What is the manpower available in your group for the next 2-3 months?
What are the developments to your fake lepton estimate that you envisage to focus on in the
short-medium term?
In next two-three months,
Padua group has no manpower available for the FR studies.
A PhD thesis about seesaw type III in three leptons final state
is ending (Jan 30 th 2014),
updated FR estimation could be included in the future PAS.
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Thank you very much !!!
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Backup slides
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EXO seesaw type III
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EXO seesaw type III
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