Inclusive SUSY searches

1
Inclusive SUSY searches using Jets, Missing E
and Leptons
T
Universität Freiburg
Debra Lumb, Stephan Horner, Sascha
Caron, Riccardo Bianchi, Xavier Portell, Johannes
Asal
2
Introduction
Importance of these analyses

• In many SUSY models leptons abundantly produced
  with
• jets in cascade decays of gluinos/squarks.
• In some models taus predominantly produced.
• Good signal to background ratio (shown here).

Organisation
Freiburg, Wisconsin, Tokyo, Cern and Belgrad.
Lepton (e,?)
CSC 5
Freiburg (2 groups) and Tokyo.
Tau
20th September 2007
Debra Lumb
1
3
Inclusive search using electrons

• TDR style event selection
• E gt max(100GeV, 0.2 Meff)
• At least 4 jets with
• p gt (100, 50, 50, 50) GeV
• Transverse sphericity gt 0.2
• No ? with p gt 20 GeV
• Exactly one e with
• p gt 20 GeV

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T
T
T
Investigated by Stephan Horner and Riccardo
Bianchi
20th September 2007
Debra Lumb
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4
Improvements - Transverse Mass Cut
Before cut
After cut
Good improvement
20th September 2007
Debra Lumb
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5
Electron Reconstruction
isEm medium electrons with standard SUSY cuts
Efficiency 80
Purity 70
Low purity due to overlap and ETCONE20 bug -
under study
20th September 2007
Debra Lumb
4
6
Inclusive search using muons

• TDR style event selection
• E gt max(100GeV, 0.2 Meff)
• At least 4 jets with
• p gt (100, 50, 50, 50) GeV
• Transverse sphericity gt 0.2
• No e with p gt 20 GeV
• Exactly one ? with
• p gt 20 GeV

T
T
T
T
Investigated by Stephan Horner and Riccardo
Bianchi
20th September 2007
Debra Lumb
5
7
Improvements - Transverse Mass Cut
Before cut
After cut
Some improvement but not as good as for
electrons
Before cut
20th September 2007
Debra Lumb
6
8
Muon Reconstruction
Isolated MuID muons with standard SUSY cuts
Efficiency 80
Purity 100
Almost no fake muons!
20th September 2007
Debra Lumb
7
9
Inclusive search using taus

• TDR style event selection
• E gt max(100GeV, 0.2 Meff)
• At least 4 jets with
• p gt (100, 50, 50, 50) GeV
• Transverse sphericity gt 0.2
• No e or ? with p gt 20 GeV
• At least one tau with
• p gt 40 GeV

T
T
T
T
Investigated by Debra Lumb and Xavier Portell
20th September 2007
Debra Lumb
8
10
Improvements - Transverse Mass Cut
Before cut
After cut
Main background is top!
20th September 2007
Debra Lumb
9
11
Improvements - Cut on the top mass?
Before cut on M
After cut on M
T
T
Most events taken by transverse mass cut
20th September 2007
Debra Lumb
10
12
Tau Reconstruction
TauRec taus with likelihood gt 4
Asking a few jets, efficiency almost sample
independent
Investigated by Xavier Portell and Johannes Asal
20th September 2007
Debra Lumb
11
13
Moving Forward
Current analyses
? e Try harsher M cuts, compare with other
groups
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? ?Try harsher M cuts, compare with other
groups
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? ? Investigate top background and try to reduce
it
Possible extensions of these analyses

• Similar but with 2 electrons, 2 muons,
• Similar but with 2 jets, 3 jets,

To watch our progress
http//hep.uni-freiburg.de/AnalysisArea/V12_Valida
tion/index.xhtml
20th September 2007
Debra Lumb
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Backup Slides
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Samples
20th September 2007
Debra Lumb
Backup