# Presentation: 671730

## Global Tracking for EM-ID

-  Introduction
-  Topics
-  EMReco
-  SEMReco
-  Conclusion

- tracking meeting                                                                                                                      F. Fleuret

- 06/20/00

## Introduction

- Global Tracking ?
- Used for electron reconstruction
- Electron reconstruction
- EM-ID has two packages for electron reconstruction
- EMReco
- package designed to reconstruct high energy electrons (well developed)
- SEMReco
- package designed to reconstruct low energy electrons (still under development)

- tracking meeting                                                                                                                      F. Fleuret

- 06/20/00

## Topics

- This talk is based on :
- test of EMReco using Z ee
- development of SEMReco using single electrons and Z bbar events
- EMReco
- aim
- tracking in EMReco
- SEMReco
- aim
- tracking in SEMReco

- tracking meeting                                                                                                                      F. Fleuret

- 06/20/00

## EMReco (cont’d)

- tracking in EMReco
- GTrackContentID = 401  SMT+CFT tracks
- sample used :
- 10000 Zee (PYTHIA) with 1.1min bias events
- reconstructed with t92 (latest version of d0reco)
- define 2  regions computing the e detector position
- CC particle   < 1.       > 0.025 from module edges
- EC particle   1.9 < < 2.5         all 
- compute 2 efficiencies:
- 1) after EM selections   calorimeter + PreShower selections
-     (selections based on clusters informations)
- 2) after track selections    track-EM selections match

- tracking meeting                                                                                                                      F. Fleuret

- 06/20/00

## tracking in EMReco (CC+CC events)
MC events

after EM selections (Calo+PS) :

after EM & track selections :

- MC events
- after EM selections (Calo+PS) :
- after EM & track selections :

**EMReco (cont’d)**

**100%**

- 87%  (93% per e)

- tracking meeting                                                                                                                      F. Fleuret

- 06/20/00

## tracking in EMReco (CC+CC events)
after EM selections (Calo+PS) :

after EM select.+ ask for 2 tracks                    (without matching):

after EM & track selections:

- tracking in EMReco (CC+CC events)
- after EM selections (Calo+PS) :
- after EM select.+ ask for 2 tracks                    (without matching):
- after EM & track selections:

**EMReco (cont’d)**

- 87%  (93% per e)

- 99%

- tracking meeting                                                                                                                      F. Fleuret

- 06/20/00

## tracking in EMReco (EC+EC events)
MC events

after EM selections (Calo+PS) : 

after EM & track selections :

- tracking in EMReco (EC+EC events)
- MC events
- after EM selections (Calo+PS) :
- after EM & track selections :

**EMReco (cont’d)**

**100%**

- 36%  (60% per e)

- Tracking only

- tracking meeting                                                                                                                      F. Fleuret

- 06/20/00

## tracking in EMReco (EC+EC events)
after EM selections (Calo+PS) : 

after EM select.+ ask for 2 tracks                    (without matching):

after EM & track selections:

- tracking in EMReco (EC+EC events)
- after EM selections (Calo+PS) :
- after EM select.+ ask for 2 tracks                    (without matching):
- after EM & track selections:

**EMReco (cont’d)**

- 36%  (60% per e)

- 100%

- tracking meeting                                                                                                                      F. Fleuret

- 06/20/00

## SEMReco

- aim
- most of the low energy electrons are in (or near) a jet
-     hard to find a cluster  need to use tracks for ID
- better energy resolution using tracker for up to~10GeV

- Tracks

- PreShower

- Calorimeter

- Jets

- Jet Finder

- Track Finder

- PS Finder

- EM Finder

- SEMcandidate

- tracking meeting                                                                                                                      F. Fleuret

- 06/20/00

## SEMReco (cont’d)

- structure of SEMReco

- tracking meeting                                                                                                                      F. Fleuret

- 06/20/00

## SEMReco (cont’d)

- tracking in SEMReco
- GTrackContentID = 401  SMT+CFT tracks
- two samples have been used:
- single electrons
- PT = 3, 4, 5, 10, 20 GeV        = [0,2]         -1.2<<1.2
- vertex smearing : x = y = 1.0 cm           z = 28.0 cm
- PT > 1.5 GeV
- Z  bbar
- no minimum bias event
- vertex smearing : x = y = 0.0 cm           z = 28.0 cm
- select CC electron events  _detector(electrons) < 1
- PT > 1.5 GeV

- tracking meeting                                                                                                                      F. Fleuret

- 06/20/00

## SEMReco (cont’d)

- single electrons study :
- reconstructed tracks .vs. MC electrons
-  = MC - track
-  = MC - track
- ~93% of electrons are in x = 0.008 x 0.008

- tracking meeting                                                                                                                      F. Fleuret

- 06/20/00

## SEMReco (cont’d)

**SEMReco (cont’d)**

- Z  bbar study :
- electron tracks = reconstructed tracks which match
-                               MC electrons.

- <tracking eff. only> ~ 75% / 93% ~ 81%

- <eff.> ~ 75%

- Elect. Tracks/MC elec.

- tracking meeting                                                                                                                      F. Fleuret

- 06/20/00

## Conclusion

- Z ee (EMReco) :
- CC+CC electrons
- tracking  main source of electron ID inefficiency
-  tracking efficiency ~ 93% per electron
- EC+EC electrons
- tracking  main source of electron ID inefficiency
- tracking efficiency ~ 60% per electron
- Z  bbar (SEMReco) : (CC electrons only)
- tracking  main source of electron ID inefficiency
- tracking efficiency ~ 81% per electron

- tracking meeting                                                                                                                      F. Fleuret

- 06/20/00