1. Diphoton+MET: Update on Plans and Progress
Bruce Schumm
SCIPP
On Behalf of the Photon+X Working Group
La Plata, LPNHE Paris, Milano, Tokyo Tech, UCSC
21 January 2016

2. But First: Photon + jets: status and next steps
01/11/12
01/11/12
Optimization and Control Regions studies (including fits and normalization factors) are done and results are documented in the backup note.
Data driven background estimates for jets faking photon will be based on the proposed ABCD method, but need to be adapted to the photon+jets scenario with the corresponding selection (contribution is very small in SR anyways).
Systematics
Tools for systematics concerning object identification and calibration are in place in SUSYTools but the corresponding uncertainties still need to be evaluated.
Signal theory systematics are already evaluated.
Background theory systematics need to be evaluated.
Validation Regions are in place, need to run and have a preliminary look at the distributions (MC based backgrounds and no systematics yet).
Back to Diphotons… 2 2

3. Recent Progress to be Reported
Signal Grid
Optimization
EW (e  ) background
e   fake rate estimation
QCD ( and j  ) backgrounds
Irreducible backgrounds
W control sample
Z cross section scale factor
Plans
January

4. January

5. January

6. January

7. Resubmit 12 failed points very soon…
Comparison of kinematics between old and new (1300,1290) point checks out
Resubmit 12 failed points very soon…
January

8. New: minimum background uncertainty of b = 0.2 events
January

9. Optimization: (mgluino,mbino) = (1500,100)
January

10. Optimization: (mgluino,mbino) = (1500,1300)
January

11. Optimization Results
Results suggest single SR with the following selection cuts:
pT > 75 GeV
(jet,MET) > 0.5
Etmiss > 175 GeV
Meff > 1500 GeV
Relative to the 8 TeV analysis, we have
Introduced background uncertainty in the optimization
Have x10 less luminosity
This seems to lessen emphasis on ultra-low background, lead to optimization point that is very inclusive of the signal, de-emphasizing the differences between the two focus points.
January

12. Background Estimation
EW (e  ) Background
e   fake rate estimation
QCD (jet  ) Background
Irreducible Background
Wgg (via control sample)
Zgg (via Sherpa normalized to Bozzi et al)
January

13. e   Fake Rate
Slightly new approach: no distinction between “tag” and “probe”; instead, just look at ee and e pairs within the Z mass region
Consider both electron and photon objects down to 25 GeV ee e
January

14. e   Fake Rate Continued
Form 2D grids in , pT
Two entries for ee events; only photon for e events
Ratio of grids gives fake rate as a function of , pT
Have required e+e- to be back-to-back; may limit pT reach of study
Are looking into removing this requirement
January

15. January

16. QCD Background Estimate
Old approach:
“Data” in above plot is pseudophoton control sample
 is from MC
Use MET shape of pseudophoton sample, after subtracting off  contribution, to estimate QCD background
July

17. New Approach: “ABCD” Method
Real diphoton background from  MC
Jet   contribution from date-driven fake factor via “ABCD” method
Combination normalized in low-MET region
Pseudo-photon selection from monophoton analysis
Fake factor definitions
January

18. Fake-factor give by ratio of isolated to anti-isolated pseudo-photons
Jet   Fake Factor
Fake-factor give by ratio of isolated to anti-isolated pseudo-photons
In Progress
January

19. W Control Sample
January

20. W Control Sample
January

21. Z Background
January

22. Z Background
January

23. Summary/Outlook Signal Grid, optimization essentially done
 Single SR for the 2015 analysis
EW (e  ) background: Almost done; e   fake rate measurement being refined
QCD ( and j  ) backgrounds: Objects defined and final studies underway
Irreducible backgrounds
W control sample defined
Z cross section scale factor determination almost complete
Still Needed: Validation study (e.g. 100 < Etmiss < 150)
Then UNBLINDING (backup note being developed in parallel with analysis)
January

24. Monophoton Pseudophoton Def’n