HepLorentzVector

java.lang.Object
- hephysics.vec.HepLorentzVector

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

LParticle
```
public class HepLorentzVector
extends Object
implements Serializable
```
a HepLorentzVector (4-vector). It can hold either space-coordinate and time (x,y,z,t) or 4-momentum (px,py,pz,energy).

See Also:

Serialized Form

Constructor Summary

Constructors
Constructor and Description
`HepLorentzVector()` Default Lorentz vector constructor
`HepLorentzVector(double[] x, double t)` Define a Lorentz vector
`HepLorentzVector(double x, double y, double z, double t)` Define a Lorentz vector This can either be (x,y,z,time) or (px,py,pz,energy)
`HepLorentzVector(float[] x, double t)` Define a Lorentz vector
`HepLorentzVector(Hep3Vector v, double t)` Define Lorentz vector

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`add(HepLorentzVector parent)` Add 2 Lorentz vectors
`HepLorentzVector`	`add(HepLorentzVector v, HepLorentzVector w)` Add 2 vectors
`double`	`angle(HepLorentzVector momentum)` Angle between 2 vectors
`void`	`boost(double bx, double by, double bz)` Lorentz Boost using 3-vector
`HepLorentzVector`	`boost(HepLorentzVector fourVector, Hep3Vector boostVector)` Boost fourVector with boostVector.
`HepLorentzVector`	`boost(HepLorentzVector fourVector, HepLorentzVector refFourVector)` Boost fourVector into system of refFourVector.
`Hep3Vector`	`centerOfMass(List<HepLorentzVector> vecSet)` Return a center mass vector
`HepLorentzVector`	`copy()` Make exact copy
`double`	`cosTheta()` cosTheta
`double`	`dot(HepLorentzVector v, HepLorentzVector w)` Dot product
`double`	`e()` Get energy
`boolean`	`equals(Object obj)` Compre 2 vectors
`double`	`et()` Transverse energy.
`double`	`et2()` Transverse energy squared.
`double`	`getE()` Get energy (as e())
`double`	`getEta()` Get a pseudorapidity: eta=-ln (tan (theta/2)) )
`double`	`getT()` Get time (as t())
`Hep3Vector`	`getV3()` Get 3-vector
`int`	`hashCode()` Hash code
`double`	`invariantMass()` Same as m().
`double`	`invariantMass2()` Same as m2().
`boolean`	`isLightlike(double epsilon)` is spacelike?
`boolean`	`isSpacelike()` Is particle spacelike (i.e restMass2() smaller than 0)
`double`	`m()` Invariant mass.
`double`	`m2()` Invariant mass squared
`double`	`mag()` Magnitude sqrt(x2+y2+z**2)
`double`	`mag2()` Magnitude squared: t()t() - v.mag2() or e()e() - v.mag2().
`double`	`mt()` Transverse mass.
`double`	`mt2()` Transverse mass: e()e() - pz()pz()
`HepLorentzVector`	`mult(double scalar, HepLorentzVector v)` Multiply by a scaler
`Hep3Vector`	`neg(Hep3Vector v)`
`HepLorentzVector`	`neg(HepLorentzVector v)` Inverse
`double`	`perp()` Transverse momentum.
`double`	`perp2()` Transverse momentum squared
`double`	`phi()` Phi
`double`	`pseudoRapidity()` Pseudorapidity.
`double`	`px()` Get X position or (Px,Py,Pz)
`double`	`py()` Get Y position or Py
`double`	`pz()` Get Z position ot Pz
`double`	`rapidity()` Rapidity.
`double`	`restMass2()` Rest mass squared -- same as m2()
`void`	`setE(double e)` Set energy
`void`	`setPx(double px)` Set Px
`void`	`setPy(double py)` Set Py
`void`	`setPz(double pz)` Set Pz
`void`	`setT(double t)` Set time
`void`	`setV3(double x, double y, double z)` Set 3-vector position or Px,Py,Pz
`void`	`setV3(Hep3Vector v)` Set 3-vector
`void`	`setX(double x)` Set X position.
`void`	`setY(double y)` Set Y position.
`void`	`setZ(double z)` Set Z position.
`double`	`skp(HepLorentzVector momentum)` Useful: for x1x2+y1y2+z1*z2
`HepLorentzVector`	`sub(HepLorentzVector v, HepLorentzVector w)` Subtract 2 vectors
`double`	`t()` Get time
`double`	`theta()` Get theta angle
`String`	`toString()` Convert to string
`Hep3Vector`	`v3()` Get 3-vector
`double`	`x()` Get X position or Px
`double`	`y()` Get Y
`double`	`z()` Get Z position or Pz

Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - HepLorentzVector
```
public HepLorentzVector()
```
    Default Lorentz vector constructor
  - HepLorentzVector
```
public HepLorentzVector(double x,
                        double y,
                        double z,
                        double t)
```
    Define a Lorentz vector This can either be (x,y,z,time) or (px,py,pz,energy)
    
    Parameters:
    
    x - X position (or Px)
    
    y - Y position (or Py)
    
    z - Z position (or Pz)
    
    t - time or energy
  - HepLorentzVector
```
public HepLorentzVector(double[] x,
                        double t)
```
    Define a Lorentz vector
    
    Parameters:
    
    x - 3-vector position or momentum
    
    t - time or energy
  - HepLorentzVector
```
public HepLorentzVector(float[] x,
                        double t)
```
    Define a Lorentz vector
    
    Parameters:
    
    x - 3-vector with position or 3-momentum
    
    t - time or energy
  - HepLorentzVector
```
public HepLorentzVector(Hep3Vector v,
                        double t)
```
    Define Lorentz vector
    
    Parameters:
    
    x - 3-vector with position or 3-momentum
    
    t - time or energy
- Method Detail
  - setV3
```
public void setV3(Hep3Vector v)
```
    Set 3-vector
    
    Parameters:
    
    v - position 9x,y,z)
  - setV3
```
public void setV3(double x,
                  double y,
                  double z)
```
    Set 3-vector position or Px,Py,Pz
    
    Parameters:
    
    x - X
    
    y - Y
    
    z - Z
  - px
```
public double px()
```
    Get X position or (Px,Py,Pz)
    
    Returns:
    
    X
  - py
```
public double py()
```
    Get Y position or Py
    
    Returns:
    
    Y
  - pz
```
public double pz()
```
    Get Z position ot Pz
    
    Returns:
    
    Z
  - x
```
public double x()
```
    Get X position or Px
    
    Returns:
    
    X
  - y
```
public double y()
```
    Get Y
    
    Returns:
    
    Y
  - z
```
public double z()
```
    Get Z position or Pz
    
    Returns:
    
    Z
  - e
```
public double e()
```
    Get energy
    
    Returns:
  - getE
```
public double getE()
```
    Get energy (as e())
    
    Returns:
  - setPx
```
public void setPx(double px)
```
    Set Px
    
    Parameters:
    
    px -
  - setPy
```
public void setPy(double py)
```
    Set Py
    
    Parameters:
    
    py -
  - setPz
```
public void setPz(double pz)
```
    Set Pz
    
    Parameters:
    
    pz -
  - setX
```
public void setX(double x)
```
    Set X position.
    
    Parameters:
    
    x - position.
  - setY
```
public void setY(double y)
```
    Set Y position.
    
    Parameters:
    
    y - Y position.
  - setZ
```
public void setZ(double z)
```
    Set Z position.
    
    Parameters:
    
    z - X position.
  - add
```
public void add(HepLorentzVector parent)
```
    Add 2 Lorentz vectors
    
    Parameters:
    
    parent -
  - mt2
```
public double mt2()
```
    Transverse mass: e()*e() - pz()*pz()
    
    Returns:
  - mag2
```
public double mag2()
```
    Magnitude squared: t()*t() - v.mag2() or e()*e() - v.mag2(). This corresponds to the invariant mass squared
    
    Returns:
  - boost
```
public void boost(double bx,
                  double by,
                  double bz)
```
    Lorentz Boost using 3-vector
    
    Parameters:
    
    bx - X
    
    by - Y
    
    bz - Z
  - setE
```
public void setE(double e)
```
    Set energy
    
    Parameters:
    
    e - energy
  - setT
```
public void setT(double t)
```
    Set time
    
    Parameters:
    
    t - time
  - t
```
public double t()
```
    Get time
    
    Returns:
    
    time
  - getT
```
public double getT()
```
    Get time (as t())
    
    Returns:
  - v3
```
public Hep3Vector v3()
```
    Get 3-vector
    
    Returns:
    
    3-vector
  - et2
```
public double et2()
```
    Transverse energy squared.
  - et
```
public double et()
```
    Transverse energy.
    
    Returns:
  - restMass2
```
public double restMass2()
```
    Rest mass squared -- same as m2()
    
    Returns:
  - mt
```
public double mt()
```
    Transverse mass.
    
    Returns:
  - invariantMass2
```
public double invariantMass2()
```
    Same as m2().
    
    Returns:
  - m2
```
public double m2()
```
    Invariant mass squared
    
    Returns:
    
    t**2 - x**2-y**2-z**2
  - invariantMass
```
public double invariantMass()
```
    Same as m(). If m2() is negative then -sqrt(-m2()) is returned.
    
    Returns:
  - m
```
public double m()
```
    Invariant mass. If m2() is negative then -sqrt(-m2()) is returned.
    
    Returns:
    
    invariant mass
  - isSpacelike
```
public boolean isSpacelike()
```
    Is particle spacelike (i.e restMass2() smaller than 0)
    
    Returns:
    
    true if spacelike
  - isLightlike
```
public boolean isLightlike(double epsilon)
```
    is spacelike?
    
    Parameters:
    
    epsilon - precision
    
    Returns:
  - dot
```
public double dot(HepLorentzVector v,
                  HepLorentzVector w)
```
    Dot product
    
    Parameters:
    
    v -
    
    w -
    
    Returns:
  - add
```
public HepLorentzVector add(HepLorentzVector v,
                            HepLorentzVector w)
```
    Add 2 vectors
    
    Parameters:
    
    v -
    
    w -
    
    Returns:
  - sub
```
public HepLorentzVector sub(HepLorentzVector v,
                            HepLorentzVector w)
```
    Subtract 2 vectors
    
    Parameters:
    
    v -
    
    w -
    
    Returns:
  - mult
```
public HepLorentzVector mult(double scalar,
                             HepLorentzVector v)
```
    Multiply by a scaler
    
    Parameters:
    
    scalar -
    
    v -
    
    Returns:
  - neg
```
public HepLorentzVector neg(HepLorentzVector v)
```
    Inverse
    
    Parameters:
    
    v -
    
    Returns:
  - neg
```
public Hep3Vector neg(Hep3Vector v)
```
  - centerOfMass
```
public Hep3Vector centerOfMass(List<HepLorentzVector> vecSet)
```
    Return a center mass vector
    
    Parameters:
    
    vecSet -
    
    Returns:
  - boost
```
public HepLorentzVector boost(HepLorentzVector fourVector,
                              Hep3Vector boostVector)
```
    Boost fourVector with boostVector. Note, that beta=abs(boostVector) needs to be 0 < beta < 1.
  - boost
```
public HepLorentzVector boost(HepLorentzVector fourVector,
                              HepLorentzVector refFourVector)
```
    Boost fourVector into system of refFourVector.
  - cosTheta
```
public double cosTheta()
```
    cosTheta
    
    Returns:
  - phi
```
public double phi()
```
    Phi
    
    Returns:
  - perp
```
public double perp()
```
    Transverse momentum.
    
    Returns:
    
    pt
  - perp2
```
public double perp2()
```
    Transverse momentum squared
    
    Returns:
    
    pt*pt
  - angle
```
public double angle(HepLorentzVector momentum)
```
    Angle between 2 vectors
    
    Parameters:
    
    momentum -
    
    Returns:
  - theta
```
public double theta()
```
    Get theta angle
    
    Returns:
  - pseudoRapidity
```
public double pseudoRapidity()
```
    Pseudorapidity. eta=-ln (tan (theta/2)) )
    
    Returns:
  - rapidity
```
public double rapidity()
```
    Rapidity. 0.5*log( (m+z)/(m-z) );
    
    Returns:
  - getEta
```
public double getEta()
```
    Get a pseudorapidity: eta=-ln (tan (theta/2)) )
    
    Returns:
    
    pseudorapidity
  - getV3
```
public Hep3Vector getV3()
```
    Get 3-vector
    
    Returns:
    
    3-vector
  - mag
```
public double mag()
```
    Magnitude sqrt(x**2+y**2+z**2)
    
    Returns:
  - skp
```
public double skp(HepLorentzVector momentum)
```
    Useful: for x1*x2+y1*y2+z1*z2
    
    Parameters:
    
    momentum -
    
    Returns:
  - equals
```
public boolean equals(Object obj)
```
    Compre 2 vectors
    
    Overrides:
    
    equals in class Object
  - copy
```
public HepLorentzVector copy()
```
    Make exact copy
    
    Returns:
    
    new copy
  - hashCode
```
public int hashCode()
```
    Hash code
    
    Overrides:
    
    hashCode in class Object
  - toString
```
public String toString()
```
    Convert to string
    
    Overrides:
    
    toString in class Object

Class HepLorentzVector

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

HepLorentzVector

HepLorentzVector

HepLorentzVector

HepLorentzVector

HepLorentzVector

Method Detail

setV3

setV3

px

py

pz

x

y

z

e

getE

setPx

setPy

setPz

setX

setY

setZ

add

mt2

mag2

boost

setE

setT

t

getT

v3

et2

et

restMass2

mt

invariantMass2

m2

invariantMass

m

isSpacelike

isLightlike

dot

add

sub

mult

neg

neg

centerOfMass

boost

boost

cosTheta

phi

perp

perp2

angle

theta

pseudoRapidity

rapidity

getEta

getV3

mag

skp

equals

copy

hashCode

toString