1. The others’ latest result about SUSY search with same-sign dimuon
Zang Jingjing

2. Three main topics about leptonic SUSY search
Muon+Jets+MET (Nmuon>=1)
OS dimuons+Jets+MET ( it can measure the end point in inv. mass of two muons)
SS dimuons+Jets+MET

3. Supersymmetry events simulation
LM1 point is chosen for selection optimization

4. SM backgrounds
Multi-jets QCD (no Feynman diagram with similar final states, but large cross section
events 10 fb pt bins)
Top pair (most important background
events 6.9pb-1 )
Single W and Z (
10 pb pt bins )
Diboson(WW, ZZ,WZ)+jets(
events: 10 pb-1 )

5. Cuts optimization
10 pb-1 background events, only 1.5±0.3 events remained, and comes solely from ttbar production.

6. Systematic uncertainties

7. Result
Optimized cuts are used in a scan across the (m0m1/2)plane. The reuslt show 5σ reach contour with several integrated luminosities .

8. Following is their recent work
Above is the others’ work about 2 years ago
Following is their recent work

9. Now what?- Adding electrons!

10. What if we adding electron
Fake rate for electrons is HUGE(in comparsion to that of muons)
- But if we manage to clean them…
we could gain factor of 3-4 in statistics!
What about taus?
- if we can do that – it would be even better, and will gain even larger factor.
BUT: RECO efficiencies and all that are worse for electrons and taus.
More? – Unfortunately ( it looks like ) we have only 3 generations…

11. So: electrons A detailed investigation of electrons
- Used most up-to-data electron ID variables, sigma(iEta,iEta)included
- Used robust electron classes and robust electron ID variables recommended by Egamma experts for early data analyses
- before even new “default recommended” cut sets prepared by Egamma group, they devised a set of electron ID cuts with all new variables.
Which kind of cut? They didn’t mentioned

12. How many fake electrons are out there?
Normalized to number of MC-truth electrons:

18. There maybe more background we didn’t considered.
My work plan
Background list
Multi-jets QCD
Top pair
Single W and Z
Diboson(WW, ZZ,WZ)+jets
There maybe more background we didn’t considered.