This tutorial builds directly on Tutorial 3 A Simple Analysis using Reconstructed Particles, so all the requirements apply.
The Code
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import hep.physics.jet.EventShape;
import hep.physics.jet.FixNumberOfJetsFinder;
import hep.physics.jet.JetFinder;
import hep.physics.vec.BasicHepLorentzVector;
import hep.physics.vec.HepLorentzVector;
import hep.physics.vec.VecOp;
import java.util.ArrayList;
import java.util.List;
import org.lcsim.event.EventHeader;
import org.lcsim.event.MCParticle;
import org.lcsim.event.ReconstructedParticle;
import org.lcsim.event.util.JetDriver;
import org.lcsim.util.Driver;
import org.lcsim.util.aida.AIDA;
public class SimpleAnalysis extends Driver{
int ievt = 0;
private AIDA aida = AIDA.defaultInstance();
String reconname = "PPRReconParticles";
public SimpleAnalysis() {
}
// process events
protected void process(EventHeader event) {
super.process(event);
// the particle lists
List<MCParticle> mcparticles = event
.get(MCParticle.class, "MCParticle");
List<ReconstructedParticle> jets = event.get(
ReconstructedParticle.class, "Jets");
List<ReconstructedParticle>recparticles =
event.get(ReconstructedParticle.class,"PPRReconParticles");
for (MCParticle particle : mcparticles) {
aida.cloud1D("MC particle energy").fill(particle.getEnergy());
if ( particle.getGeneratorStatus()==MCParticle.FINAL_STATE) {
aida.cloud1D("MC particle energy final").fill(particle.getEnergy());
}
if (Math.abs(particle.getPDGID())==22) {
aida.cloud1D("MC particle energy photon").fill(particle.getEnergy());
}
}
ArrayList<HepLorentzVector> recothrustlist =new ArrayList<HepLorentzVector>();
for (ReconstructedParticle particle : recparticles) {
recothrustlist.add(particle.asFourVector());
}
EventShape myrecoshape = new EventShape();
myrecoshape.setEvent(recothrustlist);
aida.cloud1D("Rec Particle Thrust").fill(myrecoshape.thrust().x());
// print out a status line
if (ievt % 50 == 0) {
System.out.println("Processed Events " + ievt);
}
ievt++;
}
}
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There are two more advanced schemes build in here , looking at MC particle detailsand using the event shape utilities
MCParticle Analysis
We can query Mc particles for their ID or if they are stable or not
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for (MCParticle particle : mcparticles) {
aida.cloud1D("MC particle energy").fill(particle.getEnergy());
if ( particle.getGeneratorStatus()==MCParticle.FINAL_STATE) {
aida.cloud1D("MC particle energy final").fill(particle.getEnergy());
}
if (Math.abs(particle.getPDGID())==22) {
aida.cloud1D("MC particle energy photon").fill(particle.getEnergy());
}
}
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We loop over all particles in the MCParticle collection, with
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particle.getGeneratorStatus()==MCParticle.FINAL_STATE) |
we ask, whether the particle is stable and with
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Math.abs(particle.getPDGID())==22 |
we ask whether this particle is a photon (PDG ID=22). all the methods are well documented in the LCIO documentation.
Thrust from the EventShape Package
The EventShape package from FreeHep Libraryalso contains a Thrust implementation, which is used in this example
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ArrayList<HepLorentzVector> recothrustlist =new ArrayList<HepLorentzVector>();
for (ReconstructedParticle particle : recparticles) {
recothrustlist.add(particle.asFourVector());
}
EventShape myrecoshape = new EventShape();
myrecoshape.setEvent(recothrustlist);
aida.cloud1D("Rec Particle Thrust").fill(myrecoshape.thrust().x());
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The EventShape package needs a List of HepLorentzVectors, which we provide by looping over all reconstructed particles
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ArrayList<HepLorentzVector> recothrustlist =new ArrayList<HepLorentzVector>();
for (ReconstructedParticle particle : recparticles) {
recothrustlist.add(particle.asFourVector());
}
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then we make a new EventShape Object, pass it the ArrayList and plot the Event Thrust (the first component of 3 member array)
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EventShape myrecoshape = new EventShape();
myrecoshape.setEvent(recothrustlist);
aida.cloud1D("Rec Particle Thrust").fill(myrecoshape.thrust().x());
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