hep.physics.jet
Class AbstractJetFinder

java.lang.Object
  hep.physics.jet.AbstractJetFinder

All Implemented Interfaces:

JetFinder

Direct Known Subclasses:

DurhamJetFinder, GenevaJetFinder, JadeE0JetFinder, JadeEJetFinder, JadeJetFinder, JadeP0JetFinder, JadePJetFinder

public abstract class AbstractJetFinder

extends Object

implements JetFinder

Base class for jet finders

Version:

12/6/98

Author:

G.Bower

Source Code:

AbstractJetFinder.java

Field Summary

protected int	m_np
protected HepLorentzVector[]	m_part
protected double[][]	ymass

Constructor Summary

protected

AbstractJetFinder(double ycut)

Method Summary

protected double	durham_mass(HepLorentzVector part1, HepLorentzVector part2)
int	fewestTracks() Find the jet with the fewest particles
protected void	four_vector_combine(int im, int jm)
protected double	four_vector_mass(HepLorentzVector part1, HepLorentzVector part2)
protected double	geneva_mass(HepLorentzVector part1, HepLorentzVector part2)
protected double	geneva_masscut(double ycut)
double	getYCut() Obtain the current ycut
protected double	jade_mass(HepLorentzVector part1, HepLorentzVector part2)
protected void	jadeE0_combine(int im, int jm)
protected void	jadeP_combine(int im, int jm)
protected double	jadeP0_masscut(double ycut, double esum)
HepLorentzVector	jet(int index) calculate 4 vector sum for a jet
int	njets() The number of jets found
int	nParticlesPerJet(int index) Find out many particles are in a particular jet
List	particlesInJet(int index) Find out which particles are in a paricular jet
void	setAssumedMassFor3Vectors(double mass) Set the mass to use when converting 3-vectors to 4-vectors This is a static method so the mass applies to all instances of AbstractJetFinder.
void	setEvent(Collection data) Call this to input a new event to the jet finder.
void	setEvent(Collection data, Predicate cut) Call this to input a new event to the jet finder.
void	setYCut(double ycut) Set the YCut value.
protected double	standard_masscut(double ycut, double evis) There are a variety of collinear, infra-red safe jet finders available.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

m_np

protected int m_np

m_part

protected HepLorentzVector[] m_part

ymass

protected double[][] ymass

Constructor Detail

AbstractJetFinder

protected AbstractJetFinder(double ycut)

Method Detail

njets

public int njets()

Description copied from interface: JetFinder

The number of jets found

Specified by:

njets in interface JetFinder

Returns:

The number of jets found

jet

public HepLorentzVector jet(int index)

Description copied from interface: JetFinder

calculate 4 vector sum for a jet

Specified by:

jet in interface JetFinder

Parameters:

index - The index of the jet of interest

Returns:

The 4 vector of the jet

particlesInJet

public List particlesInJet(int index)

Description copied from interface: JetFinder

Find out which particles are in a paricular jet

Specified by:

particlesInJet in interface JetFinder

Parameters:

index - The index of the jet of interest

Returns:

An enumeration of the particles within the jet

nParticlesPerJet

public int nParticlesPerJet(int index)

Description copied from interface: JetFinder

Find out many particles are in a particular jet

Specified by:

nParticlesPerJet in interface JetFinder

Parameters:

index - The index of the jet of interest

Returns:

The number of particles

fewestTracks

public int fewestTracks()

Description copied from interface: JetFinder

Find the jet with the fewest particles

Specified by:

fewestTracks in interface JetFinder

Returns:

Returns the number of tracks in the jet with the fewest tracks

getYCut

public double getYCut()

Obtain the current ycut

Returns:

The current value of ycut

setYCut

public void setYCut(double ycut)

Set the YCut value. If the new value for ycut is not the same as the old ycut the jet finding will be rerun.

Parameters:

ycut - the new value to be set for ycut

setEvent

public void setEvent(Collection data)

Call this to input a new event to the jet finder.

Specified by:

setEvent in interface JetFinder

setAssumedMassFor3Vectors

public void setAssumedMassFor3Vectors(double mass)

Set the mass to use when converting 3-vectors to 4-vectors This is a static method so the mass applies to all instances of AbstractJetFinder. The default is 0.

Parameters:

mass - The new value to use

setEvent

public void setEvent(Collection data,
                     Predicate cut)

Call this to input a new event to the jet finder. Only elements of the enumeration which are accepted by the predicate will be used for jet finding.

Specified by:

setEvent in interface JetFinder

Parameters:

cut - A predicate that is applied to each element of e

standard_masscut

protected double standard_masscut(double ycut,
                                  double evis)

There are a variety of collinear, infra-red safe jet finders available. The differences between them are (1) How they determine the cutoff mass from the ycut parameter. (2) How they combine two four-vectors together as they build up the jet. (3) what mass they assign to a four-vector. The following methods are the algorithms used in these jet finders. A concrete jet finder is an extension of the AbstractJetFinder (the current class) that specifies a masscut method, a combine_particles method and a calculate_mass method.

geneva_masscut

protected double geneva_masscut(double ycut)

jadeP0_masscut

protected double jadeP0_masscut(double ycut,
                                double esum)

four_vector_combine

protected void four_vector_combine(int im,
                                   int jm)

jadeP_combine

protected void jadeP_combine(int im,
                             int jm)

jadeE0_combine

protected void jadeE0_combine(int im,
                              int jm)

four_vector_mass

protected double four_vector_mass(HepLorentzVector part1,
                                  HepLorentzVector part2)

jade_mass

protected double jade_mass(HepLorentzVector part1,
                           HepLorentzVector part2)

durham_mass

protected double durham_mass(HepLorentzVector part1,
                             HepLorentzVector part2)

geneva_mass

protected double geneva_mass(HepLorentzVector part1,
                             HepLorentzVector part2)