1. VLIMANT Jean-Roch LPNHE 13 may 2003
CAT plenary meeting
T42 algorithm
dedicated webpage :
T42 + Top_analyze +d0root_analysis
Principle & Implementation
Effect on cells
Effect on EM objects
VLIMANT Jean-Roch LPNHE 13 may 2003

2. T42 Principle : reject isolated medium cells Named after an algorithm used in H1
Reject negative energy cells
Select high signal cells (4 sigma)
Keep their significant neighbours (2 sigma)
Thresholds 2 is 2.5 at the moment

3. cal_t42 Package created after cal_nada classes
Calt42Struct : neighbourhood object
Calt42 : container for cell lists
Calt42Chunk : container for Calt42 object
Calt42Reco :
Does the cleaning and creates a Calt42Chunk with rejected cells and modify/or not the CalDataChunk (killing/shadow mode).
Get the neighbourhood info from a Calt42Struct object which allows a linear algorithm complexity.
Calt42Combine :
When shadow mode in d0reco : produces a clean CalDataChunk
When killing mode in d0reco : produces a un-clean CalDataChunk
And registerers RegCalt42Reco RegCalt42Combine

4. Calt42Reco 1/2

5. Calt42Reco 2/2

6. Calt42Struct class content
Objects
spine : array[81600] of structured object
Mapped to ieta, iphi, layer by : INDEX = iphi + 64( layer - 1 ) ( ieta + 37 ) - 1
Structured object fields
sigma : tells the noise rms of the cell
pointers to all possible neighbors within the array
single pointer to be assigned to a CalCell available in CalDataChunk
Methods
Access
Fields initialiaser
The Neighbourhood information is read from the file STRUCTURE.dat

7. Calt42Struct use in Calt42Reco

8. Calt42Struct Neighbourhood information http://www-d0. fnal
Regular cells
normal
out of fine layers (3,4,5,6)
near fine layers (2,7)
Layer 32/33
Exceptions cells
Neighbours above or below splited into different layers
Intercryostat and nearby cells
How to check ?
Trust me
WebPage : check rules and pictures
Calt42Struct::PrintNeighbours(ieta,iphi,layer)
Calorimeter display : to be written

9. Calt42Combine Only for DST files
Only one parameter
Do you want the t42 cleaned CalDataChunk ?
Automatic detection of the d0reco mode by cell matching. Modification of the CalDataChunk

10. In the framework need for post-reconstruction when shadow mode
For DST / TMB
In the main rcp
String packagename = “…unpack T42 rebuild …”
T42 = < cal_t42 Calt42> // process the t42 algo or
T42 = < cal_t42 Calt42Combine> // only combine chunks
“rebuild” must reconstruct the object chunks you want to see the effect on

11. Study effects on data Data sets EM stream data 10000 evts of
WZskim-emStream-*-*.raw_p under the project name WZstreamTMBp13.06
Unstreamed data evts in files
recoT_all_ _mrg_*-*.raw_p
Global_CMT run
Min/Zero bias Wzskim evts of
Wzskim-mzbiasStream-*-*.raw_p
Under the project name mzbias_mvh.all1

12. Population report unstreamed data

13. Cells effect close to beam EC regions
More rejection than expected noise !
Too many cells with negative energy arbitrarily increases the rejection; They are not from gaussian noise only, probably due to pile-up
This is due to cell close to the beam 33-37
Negative energy rejection is unsuited to this region
Should be treated separately
Keep untouched above |ieta|=33(CH) and 32 (EM, FH)
Even lower for FH ?

14. Region Labels

15. Region report emstream data

16. Region report WZstream data with problems

17. Region report unstreamed data

18. Region report unstreamed data with problems

19. Region report minimum/zero bias data

20. Region report minimum/zero bias data with problems

21. Cells effect away from beam CC regions
Statistically noise like rejection
Always about the same number of negative cells in the event : probably noise and it is always rejected
Coherent number of rejected cells Region occupancies show signal presence
~40% on unstreamed data
Cells clustering decreases with the distance to interaction point
-/+ rejected ratio for region threshold tuning ? Although skim dependent (topology dependence)

22. Cells effect close to the beam
Still too much rejection in FH part need to be investigate
Peaks are due to
Overpopulated cells
Cell with noise problem
strange regions ?

23. Effect on EM clusters data/MC sets
Zee picked sample p evts (not used)
Filename : /rooms/living/varnes/scratch/cab/zee-p13/*/tmbfile
Zee Monte Carlo p evts
Project name ctf_p13.08_zee_sig2.5_tmb
Filename :
tmb-x _CTF z-ee_np_mcp13_hepfm007.uta.edu_null_*
Estimators study
At high/low energy : emstream
At low energy : J/ skim from Jan Stark (not used yet)

24. Effect on EM clusters Number of cells

25. Effect on EM clusters Number of cells

26. Effect on EM clusters estimators pT<13 GeV

27. Effect on EMid estimators pT<13 GeV

28. Effect on electrons estimators pT<13 GeV

29. Effect on EM clusters estimators pT>13 GeV

30. Effect on EMid estimators pT>13 GeV

31. Effect on electrons estimators pT>13 GeV

32. T42 effects 10% more EM cluster (10,11 ) 15% more Emid clusters
20% less above 13 GeV
15% more Emid clusters
80% more below 13GeV
11% more electrons
34% more below 13GeV

33. EM Efficiency & fake rates data set
DIEM15 stream of WZ skim 1.5Mevt
DIEM15-WZskim-emStream-*-*.raw_p (05)
under the project name Wzskim_diem
NEXT TIME

34. Conclusion Code run into p14 code Noise cleaning
T42 chunk at DST level (checked)
D0note 4146 update soon
Noise cleaning
Electronic noise seems to be deleted
Pile-up problem near beam pipe remains
Get more electrons and photons
NEXT :
Fake and efficiency
More at low energy with J/ skim