Updated R.J.Wilson May 28, 2001 - New DEdxFastRecon using HelixPid

Directions for use

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

• Launch JAS (tested mostly with 2.2.3, but I think it should work with 2.2.4).
• If all goes well, the jar files for this package will be loaded.

• First time only:
• Open and compile
• BobWFastPID.java
• BobWPIDAnalyzer.java
• PythiaParticlePropertyProvider.java
Make sure they are somewhere in your JAS classpath

• Load BobWFastPID

 
• Open a dataset

 
• the default operation in BobWFastPID is MCFast on StdHep data. The datafile on the CD in \Data\Generator Level\patt\ are good ones to try. 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 BobWFastPID.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 BobWPIDAnalyzer.
• "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 "BobWPIDAnalyzer" folder to, say, "BobWPIDAnalyzer-l2"

• Rewind the dataset.

• Find the line in BobWFastPID.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 BobWPIDAnalyzer.java.

• Load BobWFastPID

• 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
• BobWPIDAnalyzer

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

• same as detector l2 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

• detector l2 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 BobWFastPID driver in the BobWxxx PID package.