# Presentation: 676326

## Status of track reconstruction in the Near Detector

- N. Saoulidou, Fermilab 2-26-04

- N. Saoulidou (niki@fnal.gov). Fermilab

## Outline

-   Corrections of ND tracking
-   Results (using Truth Helper)
-   Summary – On going work

- N. Saoulidou (niki@fnal.gov). Fermilab

## Corrections on ND tracking 

-  Modified the way “duplicate” 3D tracks are examined :
- Initially the percentage of identical hits was examined for all track strips (U and V together).
- There were some cases were false 3D solutions existed having the correct 2D Line in one view and the wrong 2D Line in the other view.
- The code is now modified to examine percentage of identical strips in each view and keep the solution with the largest number of planes.
-  Corrected the plane number from which the Plex starts from > 121 to >=121!
- Due to that error a few quite clear tracks were missed because the code was unable to reconstruct the correct 2D line in the U view.

- N. Saoulidou (niki@fnal.gov). Fermilab

## Results of the track reconstruction after corrections (Track Completeness for all tracks using Truth Helper).

**Results of the track reconstruction after corrections (Track Completeness for all tracks using Truth Helper).**

**The track completeness improved :**
**Less events missed (zero completeness)**
**The completeness of the ones that are reconstructed has increased**

- Before

- After

- Mean = 0.70

- Mean = 0.75

- Mean = 0.86

- Mean = 0.88

- N. Saoulidou (niki@fnal.gov). Fermilab

## Results of the track reconstruction (Track Completeness for muon tracks using Truth Helper).

**Results of the track reconstruction (Track Completeness for muon tracks using Truth Helper).**

**The track completeness for muons has also increased.**

- Before

- After

-    Muons

- Mean = 0.88

- Mean = 0.90

- N. Saoulidou (niki@fnal.gov). Fermilab

## Mean = 0.80

**Results of the track reconstruction after corrections (Track Purity for all tracks using Truth Helper).**

**The track purity aslo improved :**
**Less events missed (zero purity)**
**The purity of the ones that are reconstructed has increased**

- Before

- After

- Mean = 0.83

- Mean = 0.87

- Mean = 0.90

- N. Saoulidou (niki@fnal.gov). Fermilab

## Results of the track reconstruction (Track Purity for muon tracks using Truth Helper).

**Results of the track reconstruction (Track Purity for muon tracks using Truth Helper).**

**The track purity for muons is ~ the same (very small increase)**

- Before

- After

-    Muons

- Mean = 0.96

- Mean = 0.96

- N. Saoulidou (niki@fnal.gov). Fermilab

## Things to be investigated... 

-  How is it possible the purity to be non zero and the completeness to be exactly zero...
-  Why the  Truth Helper variable completeslc (how the slicing affects the results) is not filled any more...

- N. Saoulidou (niki@fnal.gov). Fermilab

## Summary &  On going work

- Making some corrections of the  ND tracking the completeness and the purity of the reconstructed tracks has increased quite significantly and I would like to add these changes in the offline code.
- There are a few more things related with ND track finding that need to be investigated.
- I will try to learn how to use the PerfTools ( for the moment they are not available at fnalu) in order to investigate why the ND track fitting takes so much time...

- N. Saoulidou (niki@fnal.gov). Fermilab