• Original versions R.J.Wilson May 07 & 28th, and Snowmass CD-ROM July 2001 (with "BobW" prepended)

• Updated R.J.Wilson January 12, 2002 - Improved DEdxFastRecon energy loss model. New version renamed.

• R.J.Wilson January 20, 2002 - Moved to new Web address: http://hep45.hep.colostate.edu/~wilson/flc/jas/pid/fast_PID.html

• R.J.Wilson June 18, 2002 - update instructions and links

  • Remove explicit xxxxxPropertyProvider since they now appear in lcd.jar
    Add import hep.lcd.contrib.physics.* to
    FastPID_SimpleDriver_W01.java
  • Add s2 & s2dirc detector configurations to Detector_W02.jar
    

  • Make dE/dx and DIRC track map classes public and update FastPID_Wxx.jar
    
  • Allow option of no dEdx in MCFastPID_W01.java
    

  
  

Directions for use

• First, skim through the contents of this web page.

• Launch JAS (tested mostly with 2.2.3 and 2.2.5).
• If all goes well, the jar files for this package will be loaded.

• First time only:
 
• Open and compile
• FastPID_SimpleDriver_W01.java
• PIDAnalyzer_W02.java
Make sure they are somewhere in your classpath

• Load FastPID_SimpleDriver_W01
 
• Open a dataset
 
• the default operation in FastPID_W01 is MCFast on StdHep data. The optional data file download is 1000 ttbar events at 500 GeV generated by Pandora/Pythia. This is a good way to run through many events quickly.
• if you only have access to LCD full simulation data (.lcd) files, you must edit FastPID_W01.java to use TrackReco rather than MCFast (instructions in the file). The FastPID package is the same.

• Step one event (the "Step" button).
 
• if it didn't crash, you are in great shape (amazing if it works!)
• Check that there are a bunch of histograms in folder PIDAnalyzer_W01.
• "pTypes" is a good one to look at. It shows the number of each particle type that was reconstructed in that event. "noType" means no ID was possible within the default quality cuts.

• Let her rip with "Go".
 
• With the 1000 ttbar events file, it takes about 48 secs. on my 650 MHz linux laptop (<14 MB JAS memory).
• Have a look at the histograms, some may make sense without even looking into the code.

• Rename the "PIDAnalyzer_W01" histogram folder to, say, "PIDAnalyzer_W01-l2"

• Rewind the dataset.

• Find the line in FastPID_W01.java with
String detector = "l2"
and change it to
String detector = "l2dirc"
• Recompile.
• DIRC sim/recon/pid will be used automatically.
• Hit "Go".

 
• Compare the histograms and PID summary with those for the plain vanilla "l2".

 
• Repeat with your own changes to PIDAnalyzer_W01.java.

• Load FastPID_SimpleDriver_W01

• Open a dataset

• Load plugin (Job menu) - hep.lcd.plugin.LCDFastPlugin

• LCDFastPID should appear as a new menu

• Step one event.

• Play around with the LCDFastPID menu options

• Show event display needs to be selected to get access to Event Display Options.

process(LCDEvent) sequence:

• MCFast or TrackReco  (see LCD package for these)
• MCFastPID
• ParticleRecon
• PIDAnalyzer_W0n

Note: This is just an example analysis to look at the results of the fast PID package. It generates efficiency and purity matrices, and a bunch of PID related histograms.

process(LCDEvent) sequence:

• Loop over ReconstructedParticleVector
Accumulate histograms for use in purity and efficiency calculations

afterLastEvent:

• Generate purity and efficiency matrices.

process(LCDEvent) sequence:

• PID subsystem fast simulation/reconstruction -

• DEdxFastRecon
• DIRCFastRecon

 

event data changes:

• Add HashMap PIDMapsTable.

process(LCDEvent) sequence:

• ParticleTrackAssociation
• ParticleID

 

event data changes:

• add ReconstructedParticleVector of ReconstructedParticles

Constructor sequence:

• setGeometry
• setParameters
• setAcceptance

process(LCDEvent) sequence:

• Loop over ReconstructedParticleVector
Generate subsystem fast track PID values e.g.track ionisation energy loss. Use class HelixPid to get path lengths

event data changes:

• add subsystem TrackxxxxMap to PIDMapsTable e.g. TrackdEdxMap

process(LCDEvent) sequence:

• Loop over TrackList
Build ReconstructedParticleVector

event data changes:

• add ReconstructedParticle

process(LCDEvent) sequence:

• Invoke subsystem ParticleID classes e.g.
• DEdxParticleID
• DIRCParticleID

• Loop over ReconstructedParticleVector

• Combine log{likelihood} values from subsystems
• Produce summary PID information for PidInfo member of ReconstructedParticle e.g. "bestID"

event data changes:

• add PID info to ReconstructedParticles

process(LCDEvent) sequence:

• Loop over ReconstructedParticleVector
Use subsystem simulated data to produce track log{likelihood} values for e, mu, pi, K, p

event data changes:

• add subsystem log{likelihood} map (class TrackPTLnLikelihoodMap ) to the subsystems TrackxxxxMap in PIDMapsTable

ReconstructedParticle

• carries reconstructed track and pid information

TrackdEdxMap

• map of reconstructed tracks to track enery loss

TrackDIRCMap

• map of reconstructed tracks to track Cerenkov angles

TrackPTLnLikelihoodMap

• map of reconstructed tracks to ln{likelihood} info

PidInfo

• map of reconstructed track PID info.

HelixPid

• Used to get the helical path length in the tracking chamber (DEdxFastRecon).

hep.lcd.detector.l2(s2)

• same as detector l2(s2) in lcd.jar, v1.32, plus DEdx_Parameters.ini file.

Detector.ini FullBarrelResolutionBc.ini FullBarrelResolutionNbc.ini HitSmearing.ini  TrackParameters.ini ClusterParameters.ini

DEdx_Parameters.ini

hep.lcd.detector.l2dirc(s2dirc)

• detector l2(s2) plus DIRC and DEdx parameters files.

Detector.ini FullBarrelResolutionBc.ini FullBarrelResolutionNbc.ini HitSmearing.ini  TrackParameters.ini ClusterParameters.ini

DEdx_Parameters.ini DIRC_Parameters.ini DIRC01_Parameters.ini

hep.lcd.geometry.component

• DIRC_Barrel.java

Defines the DIRC_Barrel object (and sets the color) for use in the event display.

hep.lcd.plugin

LCDFastPlugin.java : Simple event display based on original package of the same name but using ReconstructedParticle and with some enhancements.

• Can display both charge and neutral MC particles, and reconstructed tracks.
• Can display particle ID labels for both MC and reconstructed tracks.
• Reconstructed track labels include a "goodness" value that is the log(likelihood) difference of the "best" choice to the next best.
• Adds a reconstructed particle table (see below).
• Can display a label with the index of the track in the reconstructed particle table.

ReconParticleTable.java : Table of ReconstructedParticle information, displays

• MC and reconstructed particle IDs
• "Goodness" value that is the log(likelihood) difference of the "best" choice to the next best.
• "notaPion" value that is the log(likelihood) difference of the "best" choice to a pion hypothesis (if it exists).
• The subsystems that contributed to the reconstructed ID (e.g. DEdx01, DIRC etc.).

• Provides particle properties used in Pandora/Pythia.
• Modified to include an equals() method -compares absolute value of PDG IDs of two ParticleType objects.
• Instantiated in FastPID driver in the PID package.
• Appears in recent versions of lcd.jar - lcd.contrib.physics
  

• Replaced by PythiaParticlePropertyProvider in FastPID_W01 driver - provides provided here to include the equals() method. {Note: This feature appears in recent versions of lcd.jar - lcd.contrib.physics}
• Modified to include an equals() method -compares absolute value of PDG IDs of two ParticleType objects.  {Note: This feature appears in recent versions of lcd.jar - lcd.contrib.physics }