A derived class for gamma gamma -> f fbar. More...

#include <SigmaEW.h>

Inheritance diagram for Sigma2gmgm2ffbar:

Public Member Functions
	Sigma2gmgm2ffbar (int idIn, int codeIn)
	Constructor.

virtual void	initProc ()
	Initialize process. More...

virtual void	sigmaKin ()
	Calculate flavour-independent parts of cross section. More...

virtual double	sigmaHat ()
	Evaluate d(sigmaHat)/d(tHat).

virtual void	setIdColAcol ()
	Select flavour, colour and anticolour. More...

virtual string	name () const
	Info on the subprocess.

virtual int	code () const

virtual string	inFlux () const
	Need to know which incoming partons to set up interaction for.

virtual int	id3Mass () const

virtual int	id4Mass () const

Public Member Functions inherited from Sigma2Process
virtual	~Sigma2Process ()
	Destructor.

virtual int	nFinal () const
	Number of final-state particles.

virtual void	set2Kin (double x1in, double x2in, double sHin, double tHin, double m3in, double m4in, double runBW3in, double runBW4in)
	Input and complement kinematics for resolved 2 -> 2 process.

virtual void	set2KinMPI (double x1in, double x2in, double sHin, double tHin, double uHin, double alpSin, double alpEMin, bool needMasses, double m3in, double m4in)
	Ditto, but for Multiparton Interactions applications, so different input.

virtual double	sigmaHatWrap (int id1in=0, int id2in=0)

virtual bool	final2KinMPI (int i1Res=0, int i2Res=0, Vec4 p1Res=0., Vec4 p2Res=0., double m1Res=0., double m2Res=0.)
	Perform kinematics for a Multiparton Interaction, in its rest frame. More...

Public Member Functions inherited from SigmaProcess
virtual	~SigmaProcess ()
	Destructor.

void	init (BeamParticle beamAPtrIn, BeamParticle beamBPtrIn, SLHAinterface *slhaInterfacePtrIn=0)
	Perform simple initialization and store pointers. More...

void	setLHAPtr (LHAupPtr lhaUpPtrIn)
	Store or replace Les Houches pointer.

void	updateBeamIDs ()
	Switch to new beam particle identities; for similar hadrons only.

virtual bool	initFlux ()
	Set up allowed flux of incoming partons. Default is no flux. More...

virtual void	set1Kin (double, double, double)

virtual void	set3Kin (double, double, double, Vec4, Vec4, Vec4, double, double, double, double, double, double)

virtual double	sigmaPDF (bool initPS=false, bool samexGamma=false, bool useNewXvalues=false, double x1New=0., double x2New=0.)

void	pickInState (int id1in=0, int id2in=0)
	Select incoming parton channel and extract parton densities (resolved). More...

virtual double	weightDecay (Event &, int, int)

virtual void	setScale ()
	Set scale, when that is missing for an external LHA process.

virtual bool	convert2mb () const
	Need to know whether to convert cross section answer from GeV^-2 to mb.

virtual bool	convertM2 () const
	For 2 -> 2 process optional conversion from \|M\|^2 to d(sigmaHat)/d(tHat).

virtual bool	isLHA () const
	Special treatment needed for Les Houches processes.

virtual bool	isNonDiff () const
	Special treatment needed for elastic and diffractive processes.

virtual bool	isResolved () const

virtual bool	isDiffA () const

virtual bool	isDiffB () const

virtual bool	isDiffC () const

virtual bool	isSUSY () const
	Special treatment needed for SUSY processes.

virtual bool	allowNegativeSigma () const
	Special treatment needed if negative cross sections allowed.

virtual int	id5Mass () const

virtual int	resonanceA () const
	Special treatment needed if process contains an s-channel resonance.

virtual int	resonanceB () const

virtual bool	isSChannel () const
	2 -> 2 and 2 -> 3 processes only through s-channel exchange.

virtual int	idSChannel () const
	NOAM: Insert an intermediate resonance in 2 -> 1 -> 2 (or 3) listings.

virtual bool	isQCD3body () const
	QCD 2 -> 3 processes need special phase space selection machinery.

virtual int	idTchan1 () const
	Special treatment in 2 -> 3 with two massive propagators.

virtual int	idTchan2 () const

virtual double	tChanFracPow1 () const

virtual double	tChanFracPow2 () const

virtual bool	useMirrorWeight () const

virtual int	gmZmode () const
	Special process-specific gamma*/Z0 choice if >=0 (e.g. f fbar -> H0 Z0).

bool	swappedTU () const
	Tell whether tHat and uHat are swapped (= same as swap 3 and 4).

int	id (int i) const
	Give back particle properties: flavours, colours, masses, or all.

int	col (int i) const

int	acol (int i) const

double	m (int i) const

Particle	getParton (int i) const

double	Q2Ren () const

double	alphaEMRen () const

double	alphaSRen () const

double	Q2Fac () const

double	pdf1 () const

double	pdf2 () const

double	thetaMPI () const
	Give back angles; relevant only for multipe-interactions processes.

double	phiMPI () const

double	sHBetaMPI () const

double	pT2MPI () const

double	pTMPIFin () const

void	saveKin ()
	Save and load kinematics for trial interactions.

void	loadKin ()

void	swapKin ()

virtual void	setIdInDiff (int, int)
	Set the incoming ids for diffraction.

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

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.

Public Attributes inherited from SigmaProcess
Z0 gamma Z0	Usage: weightDecayFlav( process). */ virtual double weightDecayFlav( Event&) {return 1.

Protected Member Functions inherited from Sigma2Process
	Sigma2Process ()
	Constructor.

virtual void	store2Kin (double x1in, double x2in, double sHin, double tHin, double m3in, double m4in, double runBW3in, double runBW4in)
	Store kinematics and set scales for resolved 2 -> 2 process. More...

virtual void	store2KinMPI (double x1in, double x2in, double sHin, double tHin, double uHin, double alpSin, double alpEMin, bool needMasses, double m3in, double m4in)
	As above, special kinematics for multiparton interactions. More...

virtual bool	setupForME ()
	Calculate modified masses and four-vectors for matrix elements. More...

Protected Member Functions inherited from SigmaProcess
	SigmaProcess ()
	Constructor.

void	addBeamA (int idIn)

void	addBeamB (int idIn)

int	sizeBeamA () const

int	sizeBeamB () const

void	addPair (int idAIn, int idBIn)

int	sizePair () const

bool	setupForMEin ()
	Calculate incoming modified masses and four-vectors for matrix elements. More...

void	setId (int id1in=0, int id2in=0, int id3in=0, int id4in=0, int id5in=0)
	Set flavour, colour and anticolour.

void	setColAcol (int col1=0, int acol1=0, int col2=0, int acol2=0, int col3=0, int acol3=0, int col4=0, int acol4=0, int col5=0, int acol5=0)

void	swapColAcol ()

void	swapCol1234 ()

void	swapCol12 ()

void	swapCol34 ()

double	weightTopDecay (Event &process, int iResBeg, int iResEnd)
	Common code for top and Higgs secondary decay angular weights. More...

double	weightHiggsDecay (Event &process, int iResBeg, int iResEnd)

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 Sigma2Process
double	tH
	Store subprocess kinematics quantities.

double	uH

double	tH2

double	uH2

double	m3

double	s3

double	m4

double	s4

double	pT2

double	runBW3

double	runBW4

Protected Attributes inherited from SigmaProcess
SusyLesHouches *	slhaPtr
	Pointer to an SLHA object.

LHAupPtr	lhaUpPtr
	Pointer to LHAup for generating external events.

bool	doVarE
	Initialization data, normally only set once.

int	nQuarkIn

int	renormScale1

int	renormScale2

int	renormScale3

int	renormScale3VV

int	factorScale1

int	factorScale2

int	factorScale3

int	factorScale3VV

double	Kfactor

double	mcME

double	mbME

double	mmuME

double	mtauME

double	renormMultFac

double	renormFixScale

double	factorMultFac

double	factorFixScale

int	higgsH1parity
	CP violation parameters for Higgs sector, normally only set once.

int	higgsH2parity

int	higgsA3parity

double	higgsH1eta

double	higgsH2eta

double	higgsA3eta

double	higgsH1phi

double	higgsH2phi

double	higgsA3phi

int	idA
	Information on incoming beams.

int	idB

double	mA

double	mB

bool	isLeptonA

bool	isLeptonB

bool	hasLeptonBeams

bool	beamA2gamma

bool	beamB2gamma

bool	hasGamma

vector< InBeam >	inBeamA
	Partons in beams, with PDF's.

vector< InBeam >	inBeamB

vector< InPair >	inPair
	Allowed colliding parton pairs, with pdf's.

double	mH
	Store common subprocess kinematics quantities.

double	sH

double	sH2

double	Q2RenSave
	Store Q2 renormalization and factorization scales, and related values.

double	alpEM

double	alpS

double	Q2FacSave

double	x1Save

double	x2Save

double	pdf1Save

double	pdf2Save

double	sigmaSumSave

int	id1
	Store flavour, colour, anticolour, mass, angles and the whole particle.

int	id2

int	id3

int	id4

int	id5

int	idSave [12]

int	colSave [12]

int	acolSave [12]

double	mSave [12]

double	cosTheta

double	sinTheta

double	phi

double	sHMass

double	sHBeta

double	pT2Mass

double	pTFin

Particle	parton [12]

Particle	partonT [12]

double	mSaveT [12]

double	pTFinT

double	cosThetaT

double	sinThetaT

double	phiT

double	mME [12]

Vec4	pME [12]

bool	swapTU
	Store whether tHat and uHat are swapped (= same as swap 3 and 4).

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

Static Protected Attributes inherited from SigmaProcess
static const double	CONVERT2MB = 0.389380
	Constants: could only be changed in the code itself. More...

static const double	MASSMARGIN = 0.1
	The sum of outgoing masses must not be too close to the cm energy.

static const double	COMPRELERR = 1e-10

static const int	NCOMPSTEP = 10

Detailed Description

A derived class for gamma gamma -> f fbar.

Member Function Documentation

virtual int id3Mass ( ) const

inlinevirtual

Flavours in 2 -> 2/3 processes where masses needed from beginning. (For a light quark masses will be used in the final kinematics, but not at the matrix-element level. For a gluon no masses at all.)

Reimplemented from SigmaProcess.

void initProc ( )

virtual

Initialize process.

Initialize process wrt flavour.

Sigma2gmgm2ffbar class. Cross section for gamma gamma -> l lbar.

Process name.

Generate massive phase space, except for u+d+s.

Charge and colour factor.

Secondary open width fraction.

Reimplemented from SigmaProcess.

void setIdColAcol ( )

virtual

Select flavour, colour and anticolour.

Select identity, colour and anticolour.

Flavours are trivial.

Colour flow in singlet state.

Reimplemented from SigmaProcess.

void sigmaKin ( )

virtual

Calculate flavour-independent parts of cross section.

Evaluate d(sigmaHat)/d(tHat) - no incoming flavour dependence.

Pick current flavour for u+d+s mix by e_q^4 weights.

Modified Mandelstam variables for massive kinematics with m3 = m4.

Calculate kinematics dependence.

Answer.

Reimplemented from SigmaProcess.

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

include/Pythia8/SigmaEW.h
src/SigmaEW.cc

Public Member Functions

Additional Inherited Members

Detailed Description

Member Function Documentation