Yet another particle class. More...

#include <StarGenParticle.h>

Inheritance diagram for StarGenParticle:

Public Types
enum	State { kNull, kFinal, kDecayed, kDocumentation, kIncident, kUnknown }

Public Member Functions
void	SetStatus (Int_t status)
	Set the status code of the particle according to the HEPEVT standard.

Int_t	GetStatus ()
	Get the status code of the particle according to the HEPEVT standard.

void	SetId (Int_t id)

Int_t	GetId ()
	Get the id code of the particle according to the PDG standard.

void	SetFirstMother (Int_t first)
	Set the first mother particle in the array of particles.

void	SetFirstMother (StarGenParticle *p)

Int_t	GetFirstMother ()
	Get the first mother particle.

void	SetLastMother (Int_t last)
	Set the last mother particle in the array of particles.

void	SetLastMother (StarGenParticle *p)

Int_t	GetLastMother ()
	Get the last mother particle.

void	SetFirstDaughter (Int_t first)
	Set the first daughter particle in the array of particles.

void	SetFirstDaughter (StarGenParticle *p)

Int_t	GetFirstDaughter ()
	Get the first daughter particle.

void	SetLastDaughter (Int_t last)
	Set the last daughter particle in the array of particles.

void	SetLastDaughter (StarGenParticle *p)

Int_t	GetLastDaughter ()
	Get the last daughter particle.

void	SetPx (Float_t px)
	Set the x-component of the momentum.

Float_t	GetPx ()
	Get the x-component of the momentum.

void	SetPy (Float_t py)
	Set the y-component of the momentum.

Float_t	GetPy ()
	Get the y-component of the momentum.

void	SetPz (Float_t pz)
	Set the z-component of the momentum.

Float_t	GetPz ()
	Get the z-component of the momentum.

Float_t	pt ()
	Returns the transverse momentum of the particle.

Float_t	pt2 ()
	Returns the transverse momentum squared.

Float_t	mt ()
	Returns the transverse mass of the particle.

Float_t	mt2 ()
	Returns the transverse mass squared.

TLorentzVector	momentum ()
	Return the 4-momentum of the particle.

void	SetEnergy (Float_t energy)
	Set the energy.

Float_t	GetEnergy ()
	Get the energy.

void	SetMass (Float_t mass)
	Set the mass.

Float_t	GetMass ()
	Get the mass.

void	SetVx (Float_t vx)
	Set the x-component of the start vertex.

Float_t	GetVx ()
	Get the x-component of the start vertex.

void	SetVy (Float_t vy)
	Set the y-component of the start vertex.

Float_t	GetVy ()
	Get the y-component of the start vertex.

void	SetVz (Float_t vz)
	Set the z-component of the start vertex.

Float_t	GetVz ()
	Get the z-component of the start vertex.

void	SetTof (Float_t tof)
	Set the tof.

Float_t	GetTof ()
	Get the tof.

void	SetIndex (Int_t i)
	Set the line number in the event record.

Int_t	GetIndex ()
	Get the line number in the event record.

void	SetStack (Int_t i)
	Set the line number in the particle stack.

Int_t	GetStack ()
	Get the line number in the particle stack.

void	SetPrimaryKey (Int_t k)

Int_t	GetPrimaryKey ()

void	SetGeneratorId (Int_t id)

Int_t	GetGeneratorId ()

void	Print (const Option_t *opts="") const
	Print the particle.

Bool_t	Simulate ()

Protected Member Functions
	ClassDef (StarGenParticle, 1)

Protected Attributes
Int_t	mIndex

Int_t	mStack

Int_t	mPrimaryKey

Int_t	mGeneratorId

Friends
class	StarPrimaryMaker

Detailed Description

Yet another particle class.

The StarGenParticle class is the class which represents event-generator particles within the event record. It is based on the HEPEVT standard, developed many years ago when FORtran ruled the earth. It stores particle information in a "table" format, specifying

mId – the Particle Data Group ID of the particle mStatus – the status code of the particle, according to the HepMC standard noted below mMother[0] – the index of the first mother of this particle in the array of particles mMother[1] – the index of the last mother of this particle in the array of particles mDaughter[0] – the index of the first daughter of this particle in the array of particles mDaughter[1] – the index of the last daughter of this particle in the array of particles

mPx, mPy, mPz, mEnergy – Specifies the four-momentum of this particle mMass – the mass of the particle as specified by the event generator mVx, mVy, mVz, mTof – the four-position of this particle

It is the developer's responsability to set these variables, usually when calling StarGenEvent::AddParticle().

Additinal variables are provided for bookkeeping purposes.

mIndex – the position of the particle within the array of particles mPrimaryKey – the position of the particle within the primary event record's array of particles mStack – the position of the particle on the geant stack, which corresponds to the ID truth in the MuDst or the "primary key" in the g2t_track record

HEPEVT status codes (as defined in the HepMC manual)

After some discussion, the authors in MCnet [18] have agreed to a clarification of the HEPEVT status codes. The Fortran Monte Carlo generators will not change their behaviour, but Sherpa, Pythia8, and Herwig++ will go to the newer usage. These are the accepted status code definitions: o 0 : an empty entry with no meaningful information and therefore to be skipped unconditionally o 1 : a final-state particle, i.e. a particle that is not decayed further by the generator (may also include unstable particles that are to be decayed later, as part of the detector simulation). Such particles must always be labelled '1' o 2 : decayed Standard Model hadron or tau or mu lepton, excepting virtual intermediate states thereof (i.e. the particle must undergo a normal decay, not e.g. a shower branching). Such particles must always be labelled 2. No other particles can be labelled 2. o 3 : a documentation entry o 4 : an incoming beam particle

o 5-10 : undefined, reserved for future standards o 11-200: an intermediate (decayed/branched/...) particle that does not fullfil the criteria of status code 2, with a generator-dependent classification of its nature. o 201- : at the disposal of the user, in particular for event tracking in the detector

Author: Jason C. Webb

Definition at line 69 of file StarGenParticle.h.

Member Enumeration Documentation

enum StarGenParticle::State

Enumerator
kNull	Null entry
kFinal	Final state particle which will not be decayed further by the event generator
kDecayed	Standard model hadron, muon or tau which has decayed. Code does not include intermediate-state hadrons.
kDocumentation	Documentation line in the record
kIncident	Incident beam particle
kUnknown	Negative numbers will signify STAR event header information