hep.physics.jet
Class EventShape

java.lang.Object
  hep.physics.jet.EventShape

public class EventShape

extends Object

Event Shape and Thrust utilities.

This is a transcription of the Jetset thrust and event shape finders into Java.

Event shape extracts from the input enumeration 3-momenta which are formed into a kind of (symmetric) momentum tensor similar to an inertia tensor. From this tensor the 3-principal axes are determined along with their associated eigenvalues.

Traditionally, the nomenclature for the three axes are:

• Thrust Axis is associated with the largest eigenvalue called the Thrust.
• Major Axis is associated with the middle eigenvalue called the Major Thrust.
• Minor Axis is associated with the smallest eigenvalue called the Minor Thrust.

Author:

G.Bower 9/21/98

Source Code:

EventShape.java

Constructor Summary

EventShape()
Call this to input a new event to the event shape routines.

Method Summary

int	getFast()
double	getThMomPower()
BasicHep3Vector	majorAxis()
BasicHep3Vector	minorAxis()
double	oblateness() Oblateness = Major Thrust - Minor Thrust
void	setEvent(Collection data) Call this to input a new event to the event shape routines.
void	setEvent(Collection data, Predicate cut) Call this to input a new event to the event shape routines.
void	setFast(int nf)
void	setThMomPower(double tp)
BasicHep3Vector	thrust() Element x = Thrust Element y = Major Thrust Element z = Minor Thrust
BasicHep3Vector	thrustAxis()

Methods inherited from class java.lang.Object

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

Constructor Detail

EventShape

public EventShape()

Call this to input a new event to the event shape routines.

Method Detail

setEvent

public void setEvent(Collection data)

Call this to input a new event to the event shape routines.

setEvent

public void setEvent(Collection data,
                     Predicate cut)

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

Parameters:

cut - A predicate that is applied to each element of e, or null to accept all elements

setThMomPower

public void setThMomPower(double tp)

getThMomPower

public double getThMomPower()

setFast

public void setFast(int nf)

getFast

public int getFast()

thrustAxis

public BasicHep3Vector thrustAxis()

majorAxis

public BasicHep3Vector majorAxis()

minorAxis

public BasicHep3Vector minorAxis()

thrust

public BasicHep3Vector thrust()

Element x = Thrust Element y = Major Thrust Element z = Minor Thrust

oblateness

public double oblateness()

Oblateness = Major Thrust - Minor Thrust