Transcript LHCC Comprehensive Review 2005

Thomas Ruf
VELO RZ Projection
February 2005
Motivation
Find useful projections which help to
debug the reconstruction algorithms.
Event display useful to look for the
unexpected.
Thomas Ruf
VELO RZ Projection
February 2005
VELO RZ view
RZ projection:
R = sqrt(x2 + y2), x>0
R = -sqrt(x2 + y2), x<0
Scale: R:Z = 1:8.4
Tracks crossing VELO halves might look strange, however less busy plot
compared to +RZ projection
Projection only makes sense around VELO
R-strips
 points
Phi-strips  vertical lines
Selected MCParticles can be displayed in 3d with corresponding
detector hits and reconstructed track(s)
Thomas Ruf
VELO RZ Projection
February 2005
Extrapolations
MCParticles:
Modifications to SoMCParticleCnv and SoTrStoredTrackCnv
not directly related to RZ projection
Production vertex inside Velo and decay vertex outside VELO:
Straight line defined by momentum vector
Production vertex outside Velo and decay vertex outside VELO:
Straight line connecting production vertex and decay vertices
Production vertex inside Velo and decay vertex inside VELO:
Straight line connecting production vertex and decay vertex
Tracks:
Use of parabolic extrapolator if states with momentum information available,
otherwise straight line between states
Thomas Ruf
VELO RZ Projection
February 2005
Associations
Modifications to SoEvent/Types.cpp, Panoramix/Callback.cpp
and Onx/Pages.onx
New Associations entered:
In picking mode, selecting
object and clicking right
mouse button:
MCParticle_Clusters
VeloCluster_MCParticles
Would be nice to have a generic cluster
object. Doesn’t exist at the moment,
therefore association needs to be
implemented for every cluster type.
Thomas Ruf
VELO RZ Projection
February 2005
Display
Vertices:
Production vertex:
Interaction vertex:
MCParticles:
e,u,p,k,p from B
: red
Other particles
associated to tracks : golden
Thomas Ruf
VELO RZ Projection
February 2005
Display
VELO clusters:
Used R-clusters : red
Unused R-clusters : white
Phi clusters:
magenta
Tracks:
VELO back
VELO back
VELO
VELO-TT
Forward
Match
: green yellow
: green
VELO
: cyan
: blue
: skyblue
Thomas Ruf
VELO RZ Projection
Velo-TT
February 2005
Forward
Match
Examples
Tracks crossing detector halves
All events are from B  D*p
No trigger applied
Why does x-slope changes ?
Problem with extrapolator ?
Thomas Ruf
VELO RZ Projection
February 2005
Missing b-tracks I
KL decay
Velo noise ?
b-track, non-reconstructed
 go to 3d view
Thomas Ruf
VELO RZ Projection
February 2005
3d View
Thomas Ruf
VELO RZ Projection
February 2005
Missing b-tracks Ib
Thomas Ruf
VELO RZ Projection
February 2005
Missing b-tracks II
100 mm
Thomas Ruf
VELO RZ Projection
February 2005
Missing b-tracks IIb
100 mm
Not enough hits ?
decay
Thomas Ruf
VELO RZ Projection
February 2005
Ghosts and Clones
Match track and
forward track
Downstream, 3d
Forward track is ghost, however 
Thomas Ruf
VELO RZ Projection
February 2005
Ghosts and Clones, cont.
Upstream, 2d
However, match track badly
extrapolated to primary vertex
Thomas Ruf
VELO RZ Projection
February 2005
Precise tracking
100 mm
Thomas Ruf
VELO RZ Projection
February 2005
Converted Photons
Thomas Ruf
VELO RZ Projection
February 2005
Converted Photons cont.
Thomas Ruf
VELO RZ Projection
February 2005
Conversion reconstructed
g conversion
Thomas Ruf
VELO RZ Projection
February 2005
K short
100 mm
Ks
Thomas Ruf
VELO RZ Projection
February 2005
Pile Up
3 primary vertices
100 mm
Thomas Ruf
VELO RZ Projection
February 2005
Busy Event I
Busy Event
Backward Velo tracks
cleaner than forward ?
100 mm
Thomas Ruf
VELO RZ Projection
February 2005
Busy Event II
Backward Velo tracks
cleaner than forward ?
Thomas Ruf
VELO RZ Projection
February 2005
Clean Event I
Clean Event
However all B-decay tracks
outside acceptance
Thomas Ruf
VELO RZ Projection
February 2005
Clean Event II
Another Clean Event
with most B-decay tracks
outside acceptance
100 mm
Thomas Ruf
VELO RZ Projection
February 2005
MC Truth
Need scale !
Select D* decay
tracks and
display in 3d 
Thomas Ruf
VELO RZ Projection
February 2005
To reconstruction
Thomas Ruf
VELO RZ Projection
February 2005
Random Observations I
Forward track with only 1 r-cluster ?
Thomas Ruf
VELO RZ Projection
February 2005
Random Observations II
Velo-TT tracks, extrapolation ?, 0 charge
Thomas Ruf
VELO RZ Projection
February 2005
Random Observations III
Not all Velo hits are used
Thomas Ruf
VELO RZ Projection
February 2005
Random Observations IIIa
Not all Velo hits are used
Kaon decay
Thomas Ruf
VELO RZ Projection
February 2005
Code Modifications
SoEvent/Types.cpp
Added bcflag property
Associations
SoEvent/SoMCParticleCnv.cpp
Display of vertices
Support for RZ projection, more straight line segments inside VELO
SoEvent/SoTrStoredTrackCnv.cpp
Support for RZ projection,
more straight line segments inside VELO
SbProjector.cxx:
Added –ZR projection
Temporarily moved to SoEvent/src
Several Python scripts: truf_xxx.py
Thomas Ruf
VELO RZ Projection
February 2005
Interactivity and Python
If Panoramix is started from Python, you can exit Panoramix
temporarily and access the event information directly using Python
Example: Access to objects in any keyed container:
After you finished, type
to return to Panoramix
Also possible to execute any Python script from Panoramix command
line using sys_import(‘myscript’)
Thomas Ruf
VELO RZ Projection
February 2005
End
Thomas Ruf
VELO RZ Projection
February 2005