1. 1 H → γγ analysis Maosen Zhou 02/04/2014

2. 2 For the coupling measurement,the categories are chosen to probe different Higgs production models,such as VBF,W or Z assoiciated production and ttH production.

3. 3 For this note,there are 4 parts which cover 12 categories For this note,there are 4 parts which cover 12 categories H-yy VBF tightloose VH hadronicone-leptonMETdilepton ttH hadronicleptonic PTt-eta 4 categories H-yy VBF tightloose VH hadronicone-leptonMETdilepton ttH hadronicleptonic PTt-eta 4 categories

4. 4 cross sections

5. 5 Flow-chart of event categorisation,giving the order of selection of the different categories

6. 6 VBF categories

7. 7 VBF Categories Sig: two forward jets with high PT and large rapidity separation; Higgs products lie between jets; peak in diphonton invariant mass. Bkg: ›non-resonant: direct yy pairs ;single y events with one jet fakes a photon; multi-jet events with two fake photons. ›resonant: gluon fusion Higgs produced with two jets(at least)

8. 8 Two approaches:cut-based & MVA Cut-based VBF significance: signal and ggF background from MC,non-resonant from sideband data final cut-based tight: final cut-based loose: and removing events that passed cut-based tight selection

9. 9 MVA signal from VBF MC samples bkg: › yy + jets from Sherpa › y+jets & jets+jets from data(RevISO) samples → two jets selection & precuts → separated into two parts → one to train MVA discriminant → the other one to find optimized VBF categories

10. 10 Variables (for MVA) Variables (for MVA) requriments: ›have little to no correlation to Myy; ›low susceptibility to system uncertainties

11. 11 final cuts MVA tight: MVA weight > 0.83 MVA loose: 0.3 < MVA weight < 0.83 tight / loose orthogonal?

12. 12 VH categories

13. 13 Comparison

14. 14 VH hadronic category : W/Z → jj sig: Higgs sanples with a mass of 125GeV bkg: data side-bands events and smeared yy+yj+jj smeared MC samples variables tested to find the best optimisation

15. 15 four remaining variables 20736 sets of cuts were tested! ↓

16. 16 Moriond 2013 survive! ›maximum purity 68% but with sig two times lower than Moriond ›an improvement of 16% can be reached on sig ›the real impact of those cuts is computed by doing the full statistic procedure with 14 categories defined for Moriond,but changing cuts for VH hadronic category ›uncertainty on Uvh is improved by 3% only ›improvement is computed by assuming the uncertainties will remain the same,however,in fact uncertainty will increase as the cut on PTt is tighten and a new cut Ht introduced

17. 17 One lepton category: WH → lvyy To reduce Z(ee)y bkg,a diphoton event with electrons is vetoed if 84<Mey<94GeV for the leading electron and one of photons ·variables:mT,MET,MET significance ·optimal point: MET significance > 1.5 bkg :

18. 18 MET category A higgs produced in association with W or Z may produce significant missing energy MET significance > 5, PTt > 20GeV MET significance definition?

19. 19 Dilepton category : ZH → llyy two leptons with PT>10GeV for muons and PT > 15GeV for electrons Same flavour,opposite charge leptons 70<m(ll)<110GeV These cuts lead to a ZH purity of 90%,the remaining from ttH

20. 20 bkg estimation photon purity increases with the PT, consider Z+jets bkg negligible in the signal region

21. 21 expected sig and bkg

22. 22 ttH categories

23. 23 ttH Categories ·Leptonic category: >=1 lepton,then 1 b-jet in addition to MET>20GeV or 2 b-jets with no requirement on MET ·Hadronic category: Events passing either of the 3 selections are included

24. 24 PTt-eta categories

25. 25 Remaining untagged events The categorization for events not VBF-,VH- or ttH-tagged is also reinvestigated. schematic view of the categorization of the untagged events for the previous analysis is the converted one used?

26. 26 Strategy sig: MC,sqrt(s)=8TeV,mH=125GeV bkg: baseline is to use MC.data side band (I don't understand clearly...) ↓ testing various scenarios ↓ final choice

27. 27 signal composition

28. 28 Summary of categorization

29. 29 statistics tools ? how to get /use...?_?