Gets cross sections for hadron-hadron collisions at low energies. More...

#include <SigmaLowEnergy.h>

Inheritance diagram for SigmaLowEnergy:

Public Member Functions
void	init (NucleonExcitations *nucleonExcitationsPtrIn)
	Initialize. More...

double	sigmaTotal (int idA, int idB, double eCM, double mA, double mB)
	Get the total cross section for the specified collision. More...

double	sigmaTotal (int idAIn, int idBIn, double eCMIn)

double	sigmaPartial (int idA, int idB, double eCM, double mA, double mB, int proc)
	Gets the partial cross section for the specified process. More...

double	sigmaPartial (int idAIn, int idBIn, double eCMIn, int proc)

bool	sigmaPartial (int idA, int idB, double eCM, double mA, double mB, vector< int > &procsOut, vector< double > &sigmasOut)

int	pickProcess (int idA, int idB, double eCM, double mA, double mB)
	Picks a process randomly according to their partial cross sections.

int	pickResonance (int idA, int idB, double eCM)
	Picks a resonance according to their partial cross sections. More...

bool	hasExcitation (int idAIn, int idBIn) const

void	updateResonances ()
	Update the list of internal resonances. More...

Public Member Functions inherited from PhysicsBase
void	initInfoPtr (Info &infoPtrIn)
	This function is called from above for physics objects used in a run. More...

virtual	~PhysicsBase ()
	Empty virtual destructor.

bool	flag (string key) const
	Shorthand to read settings values.

int	mode (string key) const

double	parm (string key) const

string	word (string key) const

vector< bool >	fvec (string key) const

vector< int >	mvec (string key) const

vector< double >	pvec (string key) const

vector< string >	wvec (string key) const

Static Public Attributes
static constexpr double	TINYSIGMA = 1.e-9
	Cross sections below threshold are assumed numerically equal to zero.

Friends
class	LowEnergyProcess
	LowEnergyProcess should have access to nqEffAQM for slope in t.

Additional Inherited Members
Public Types inherited from PhysicsBase
enum	Status { INCOMPLETE = -1, COMPLETE = 0, CONSTRUCTOR_FAILED, INIT_FAILED, LHEF_END, LOWENERGY_FAILED, PROCESSLEVEL_FAILED, PROCESSLEVEL_USERVETO, MERGING_FAILED, PARTONLEVEL_FAILED, PARTONLEVEL_USERVETO, HADRONLEVEL_FAILED, CHECK_FAILED, OTHER_UNPHYSICAL, HEAVYION_FAILED, HADRONLEVEL_USERVETO }
	Enumerate the different status codes the event generation can have.

Protected Member Functions inherited from PhysicsBase
	PhysicsBase ()
	Default constructor.

virtual void	onInitInfoPtr ()

virtual void	onBeginEvent ()
	This function is called in the very beginning of each Pythia::next call.

virtual void	onEndEvent (Status)

virtual void	onStat ()
	This function is called from the Pythia::stat() call.

void	registerSubObject (PhysicsBase &pb)
	Register a sub object that should have its information in sync with this.

Protected Attributes inherited from PhysicsBase
Info *	infoPtr = {}

Settings *	settingsPtr = {}
	Pointer to the settings database.

ParticleData *	particleDataPtr = {}
	Pointer to the particle data table.

Logger *	loggerPtr = {}
	Pointer to logger.

HadronWidths *	hadronWidthsPtr = {}
	Pointer to the hadron widths data table.

Rndm *	rndmPtr = {}
	Pointer to the random number generator.

CoupSM *	coupSMPtr = {}
	Pointers to SM and SUSY couplings.

CoupSUSY *	coupSUSYPtr = {}

BeamSetup *	beamSetupPtr = {}

BeamParticle *	beamAPtr = {}

BeamParticle *	beamBPtr = {}

BeamParticle *	beamPomAPtr = {}

BeamParticle *	beamPomBPtr = {}

BeamParticle *	beamGamAPtr = {}

BeamParticle *	beamGamBPtr = {}

BeamParticle *	beamVMDAPtr = {}

BeamParticle *	beamVMDBPtr = {}

PartonSystems *	partonSystemsPtr = {}
	Pointer to information on subcollision parton locations.

SigmaTotal *	sigmaTotPtr = {}
	Pointers to the total/elastic/diffractive cross sections.

SigmaCombined *	sigmaCmbPtr = {}

set< PhysicsBase * >	subObjects

UserHooksPtr	userHooksPtr

Detailed Description

Gets cross sections for hadron-hadron collisions at low energies.

Member Function Documentation

bool hasExcitation	(	int	idAIn,
		int	idBIn
	)		const

inline

For NN / N Nbar / Nbar Nbar collisions explicit excitation states. replace a generic smeared-out low-mass diffraction component.

void init ( NucleonExcitations * nucleonExcitationsPtrIn )

Initialize.

The SigmaLowEnergy class.

Initialize.

Flag to allow or suppress inelastic processes.

Mode for calculating total cross sections for pi pi and pi K.

Suppression factors in Additive Quark Model (AQM).

Mixing for eta and eta'; specifically fraction of s sbar.

Some standard masses.

Store pointer.

Fill explicit resonances.

int pickResonance	(	int	idA,
		int	idB,
		double	eCM
	)

Picks a resonance according to their partial cross sections.

Set canonical ordering.

Fail if no resonances exist.

Calculate cross section for each resonance.

Return zero if no resonances are available.

Pick resonance at random.

double sigmaPartial	(	int	idA,
		int	idB,
		double	eCM,
		double	mA,
		double	mB,
		int	proc
	)

Gets the partial cross section for the specified process.

Energy cannot be less than the hadron masses.

For K0S/K0L, take average of K0 and K0bar.

Total cross section.

Get all partial cross sections.

Return partial cross section.

bool sigmaPartial	(	int	idAIn,
		int	idBIn,
		double	eCMIn,
		double	mAIn,
		double	mBIn,
		vector< int > &	procsOut,
		vector< double > &	sigmasOut
	)

Gets all partial cross sections for the specified collision. This is used when all cross sections are needed to determine which process to execute. Returns false if no processes are available.

Gets all partial cross sections for the specified collision. Returns whether any processes have positive cross sections.

No cross sections below threshold.

If K_S/K_L + X then take the average K0 and K0bar.

If X + K_S/K_L then take the average K0 and K0bar.

Store current configuration.

Calculate total, annihilation and resonant cross sections (if needed).

Abort early if total cross section vanishes.

If inelastic is off, return only elastic cros ssection.

Calculate diffractive cross sections.

Calculate elastic cross sections.

Calculate excitation cross sections for NN.

Calculate nondiffractive as difference between total and the others.

Give warning if sigmaND is very negative.

Rescale pi pi and pi K cross sections to match Pelàez total cross section.

Rescale for pi pi below 1.42 GeV, and for pi K below 1.8 GeV

Get cross section from parameterization.

Write results to output arrays.

double sigmaTotal	(	int	idA,
		int	idB,
		double	eCM,
		double	mA,
		double	mB
	)

Get the total cross section for the specified collision.

Energy cannot be less than the hadron masses.

For K0S/K0L, take average of K0 and K0bar.

Fix particle ordering.

Get custom cross section if applicable.

Special handling for pi pi and pi K cross sections

Calculate total.

void updateResonances ( )

Update the list of internal resonances.

Use setConfig to ensure canonical ordering.

The documentation for this class was generated from the following files:

include/Pythia8/SigmaLowEnergy.h
src/SigmaLowEnergy.cc

Public Member Functions

Static Public Attributes

Friends

Additional Inherited Members

Detailed Description

Member Function Documentation